Viagra 50 mg instructions for use. How to take Viagra: instructions and rules for use

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Dosage form

Film-coated tablets 50 mg, 100 mg

Compound

One tablet contains

active substance - sildenafil citrate 70.225 mg and 140.450 mg (equivalent to sildenafil 50 mg and 100 mg),

excipients: microcrystalline cellulose, anhydrous calcium hydrogen phosphate, croscarmellose sodium, magnesium stearate,

Shell composition: blue opadry OY-LS-20921 (hypromellose, lactose, triacetin, titanium dioxide (E 171) and indigo carmine aluminum varnish (E132)), transparent opadry YS-2-19114 A (hypromellose and triacetin).

Description

Film-coated tablets, blue, biconvex, in the form of a rounded diamond marked "Pfizer" on one side and "VGR 50" (for a dosage of 50 mg) or "VGR 100" (for a dosage of 100 mg) on ​​the other side.

Pharmacotherapeutic group

Preparations for the treatment of urological diseases. Other drugs for the treatment of urological diseases, including antispasmodics. Preparations for the treatment of erectile dysfunction. Sildenafil.

ATX code G04BE03

Pharmacological properties

Pharmacokinetics

Suction

Sildenafil is rapidly absorbed after oral administration. Peak plasma concentrations (Cmax) of sildenafil are reached within 30 to 120 minutes (median 60 minutes) after oral administration on an empty stomach. The mean absolute oral bioavailability is 41% (with a range of 25-63%). After oral administration of sildenafil in the recommended dose range (25-100 mg), the area under the pharmacokinetic curve (AUC) and Cmax increase in direct proportion to the dose taken.

When taking sildenafil with food, the absorption rate decreases with an average delay in the time to reach maximum plasma concentrations (tmax) of 60 minutes and an average decrease in Cmax by 29%.

Distribution

The mean equilibrium volume of distribution (Vd) for sildenafil is 105 L, indicating its distribution in body tissues.

After oral administration of sildenafil at a single dose of 100 mg, the mean maximum total plasma concentration of sildenafil is approximately 440 ng/ml (with a coefficient of variation of 40%). Due to the fact that sildenafil (and its main circulating metabolite, N-desmethyl metabolite) is 96% bound to plasma proteins, the average maximum concentration of free sildenafil in plasma is 18 ng / ml (38 nM). Protein binding is independent of total drug concentrations.

In healthy volunteers who received sildenafil once at a dose of 100 mg, less than 0.0002% (mean 188 ng) of the dose of the drug was determined in the ejaculate 90 minutes after taking the dose.

Metabolism

In vitro studies

The metabolism of sildenafil is carried out mainly with the participation of microsomal isoenzymes of the liver CYP3A4 (main pathway) and CYP2C9 (secondary pathway) of cytochrome P450. For this reason, inhibitors of these isoenzymes can reduce, and inducers of these isoenzymes - increase the clearance of sildenafil.

By N-demethylation, the main circulating metabolite of sildenafil is formed, which undergoes further metabolism with a final elimination half-life of approximately 4 hours. The metabolite is characterized by a selectivity profile for phosphodiesterase comparable to that of sildenafil, and the in vitro activity of the metabolite in relation to phosphodiesterase type 5 (PDE-5) is approximately 50% of the activity of the parent substance of the drug.

Plasma concentrations of this metabolite are approximately 40% of sildenafil concentrations.

Sildenafil is a weak inhibitor of cytochrome P450 isoforms 1A2, 2C9, 2C19, 2D6, 2E1 and 3A4 (IC > 150 µM). Provided that the maximum concentration of sildenafil in blood plasma after taking the recommended doses of the drug is approximately 1 μm, it is unlikely that sildenafil will change the clearance of substrates of these isoenzymes.

breeding

The total clearance of sildenafil is 41 l / h, and the final half-life is from 3 to 5 hours. After oral administration, sildenafil is excreted as metabolites mainly in the faeces (about 80% of the oral dose) and to a lesser extent in the urine (about 13% of the oral dose).

Pharmacokinetics in special groups patients

Elderly patients

In healthy elderly volunteers (aged 65 years or older), there was a decrease in the clearance of sildenafil, causing an increase in plasma concentrations of sildenafil and its active N-demethylated metabolite by approximately 90% compared with those in healthy younger volunteers (18-45 years old) . Due to age-related differences in plasma protein binding, the corresponding increase in free sildenafil plasma concentration is approximately 40%.

In patients with mild or moderate renal dysfunction (creatinine clearance 30-80 ml / min), the pharmacokinetics of sildenafil after a single oral dose of 50 mg does not change. The increase in the average AUC and Cmax of the N-demethylated metabolite was up to 126% and up to 73%, respectively, compared with such indicators in people of the same age without impaired renal function. However, due to the high inter-patient variability, these differences were not statistically significant. In patients with severely impaired renal function (creatinine clearance< 30 мл/мин) клиренс силденафила снижался, что приводило к средним повышениям показателей AUC и Cmax, соответственно на 100 % и 88 % по сравнению с пациентами аналогичного возраста без нарушений функции почек. Кроме того, значения AUC и Cmax для N-деметилированного метаболита также значительно повышались - на 200 % и 79 %, соответственно.

In patients with mild to moderate liver cirrhosis (Child-Pugh stages A and B), sildenafil clearance was reduced, resulting in an increase in AUC (by 84%) and Cmax (by 47%) compared with volunteers of the same age without liver dysfunction.

The pharmacokinetics of sildenafil in patients with severe hepatic impairment has not been studied.

Pharmacodynamics

Mechanism of action

Viagra®, an oral drug for the treatment of erectile dysfunction, that is, during sexual stimulation, it restores impaired erectile function by increasing blood flow to the penis.

The physiological mechanism of penile erection involves the release of nitric oxide (NO) in the cavernous bodies upon sexual stimulation. Nitric oxide activates the enzyme guanylate cyclase, which leads to increased levels of cyclic guanosine monophosphate (cGMP), followed by smooth muscle relaxation in the cavernous bodies and increased blood flow.

Sildenafil is a strong and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE-5), which is responsible for the breakdown of cGMP in the cavernous bodies. Sildenafil has a peripheral effect on erection. Sildenafil does not have a direct relaxing effect on the isolated human corpus cavernosum, but significantly enhances the relaxing effect of NO on this tissue. When the NO/cGMP metabolic pathway is activated, as occurs during sexual stimulation, PDE-5 inhibition by sildenafil results in an increase in cGMP levels in the cavernous bodies. Therefore, to provide sildenafil with the desired productive pharmacological action sexual stimulation is needed.

Pharmacodynamic effects

In vitro studies

Sildenafil selectively acts on PDE-5, which is involved in the regulation of the erection process. The action of Viagra® on PDE-5 is stronger than on other known phosphodiesterases. This effect of Viagra® action is 10 times stronger than the effect on PDE-6, which takes part in phototransformation processes in the retina. When used in the maximum recommended doses, the selectivity of sildenafil to PDE-5 is 80 times higher than its selectivity to PDE-1, more than 700 times - selectivity to PDE-2, PDE-3, PDE-4, PDE-7, PDE-8 , PDE-9, PDE-10 and PDE-11. In particular, the selectivity of sildenafil to PDE-5 is 4000 times higher than its selectivity to PDE-3, a cAMP-specific isoform of phosphodiesterase involved in the regulation of heart contractions.

Clinical efficacy and safety

The safety and efficacy of sildenafil have been confirmed by data from long-term studies.

Indications for use

Erectile dysfunction, characterized by the inability to achieve or maintain an erection of the penis sufficient for satisfactory intercourse.

Viagra® is effective only with sexual stimulation.

Dosage and administration

For oral use.

Viagra® can be taken with or without food. However, it may take longer for Viagra® to start working if taken with food.

Dosing regimen

Use in adults

The recommended dose of Viagra® is 50 mg orally approximately 1 hour before sexual intercourse. Based on efficacy and tolerability, the dose may be increased to 100 mg. The maximum recommended dose is 100 mg.

The tablet should be swallowed whole with a glass of water.

Special patient groups

Elderly patients

In elderly patients (≥ 65 years), dose adjustment is not required.

Patients with impaired renal function

With mild to moderate renal dysfunction (creatinine clearance 30-80 ml / min), dose adjustment is not required. Due to a decrease in the clearance of sildenafil in patients with severe renal impairment (creatinine clearance< 30 мл/мин), следует рассмотреть возможность применения Виагры® в дозе 25 мг. Исходя из эффективности и переносимости препарата при необходимости, его дозу можно увеличивать поэтапно до 50 мг и до 100 мг.

Patients with impaired liver function

Due to the fact that the clearance of sildenafil is reduced in patients with impaired liver function (for example, cirrhosis), the possibility of using the drug at a dose of 25 mg should be considered. Based on the effectiveness and tolerability of the drug, if necessary, its dose can be increased in stages up to 50 mg and up to 100 mg.

Patients of childhood and adolescence

Sildenafil is not indicated for use in children (< 18 лет).

Use in patients taking other medicinal products

In order to reduce the risk of developing postural arterial hypotension in patients treated with alpha-blockers, the condition of patients receiving alpha-blockers should / stabilize the condition of patients receiving alpha-blockers before starting treatment with sildenafil. In addition, the possibility of using sildenafil should be considered, starting with a dose of 25 mg.

Side effects

When using Viagra®, undesirable effects were registered, which were classified according to the frequency of their manifestation as follows: very often (≥ 1/10), often (from ≥ 1/100 to< 1/10), нечасто (от ≥ 1/1000 до < 1/100) и редко (≥ 1/10 000 и < 1/1000).

Often

Headache

Dizziness

Color distortions of vision (chloropsia, chromatopsia, cyanopsia, erythropsia, xanthopsia), visual disturbance, blurred vision

Hyperemia, hot flashes

Nasal congestion

Dyspepsia, nausea

Hypersensitivity

Drowsiness, hypoesthesia

Lacrimation disorders (dry eye, lacrimal gland dysfunction, increased lacrimation), eye pain, photophobia, photopsia, ocular hyperemia, visual brightness, conjunctivitis

Spatial disorientation (vertigo), tinnitus

Tachycardia, palpitations

Arterial hypertension, arterial hypotension

Epistaxis, sinus congestion

Pain in the upper abdomen, gastroesophageal reflux disease, vomiting, dry mouth

Myalgia, pain in the extremities

Hematuria

Pain in chest, increased fatigue, feeling of heat

Elevated heart rate

Acute violation cerebral circulation, transient ischemic attack, seizure*, relapse convulsive attack*, fainting

Anterior non-arteritic ischemic optic neuropathy*, retinal vascular occlusion*, retinal hemorrhage, arteriosclerotic retinopathy, retinal disease, glaucoma, visual field defect, diplopia, decreased visual acuity, myopia, asthenopia, floaters vitreous body, iris disease, mydriasis, presence of iris circles in the field of vision, swelling of the eye, swelling of the eye, visual disturbance, conjunctival hyperemia, eye irritation, unusual sensation in the eye, swelling of the eyelids, discoloration of the sclera

Deafness

Sudden cardiac death*, myocardial infarction, ventricular arrhythmia*, atrial fibrillation, unstable angina

Feeling of tightness in the throat, swelling of the nose, dryness of the nasal mucosa

Oral hypoesthesia

Stevens-Johnson syndrome*, toxic epidermal necrolysis*

Penis bleeding, priapism*, hematospermia, increased erection
- irritability

*adverse events recorded only during post-marketing surveillance.

Reporting Suspected Adverse Reactions

Communication of information about suspected adverse reactions identified after registration of the medicinal product is of great importance. This allows continued monitoring of the benefit/risk balance of the medicinal product.

Healthcare professionals and patients are asked to report any adverse reactions to the address provided at the end of this package leaflet.

Contraindications

Hypersensitivity to the active substance or to any of the excipients

Simultaneous administration of drugs that are donors of nitric oxide (amyl nitrite) or nitrates in any form

Simultaneous administration with guanylate cyclase stimulants (riociguat)

severe liver failure

Hereditary degenerative diseases of the retina (for example, hereditary retinitis pigmentosa (a small number of these patients have hereditary disorders of the functions of retinal phosphodiesterases))

Loss of vision in one eye due to non-arteritic anterior ischemic optic neuropathy, whether or not the episode was associated with prior use of a PDE5 inhibitor

Arterial hypotension (BP< 90/50 мм рт. ст.)

Heavy cardiovascular diseases(eg, severe heart failure, unstable angina)

Myocardial infarction in the last 6 months

Stroke in the last 6 months

Concomitant use with CYP3A4 isoenzyme inhibitors (eg, ketoconazole, itraconazole, ritonavir, erythromycin, saquinavir, clarithromycin)

Concomitant use of drugs for the treatment of pulmonary arterial hypertension (bosentan, iloprost) and drugs containing sildenafil or any other PDE-5 inhibitor

Men with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency, or glucose-galactose malabsorption syndrome

Concomitant use with other oral or topical agents for the treatment of erectile dysfunction

Carefully:

§ anatomical deformity of the penis (including angulation, cavernous fibrosis or Peyronie's disease)

§ diseases that predispose to the development of priapism (such as sickle cell anemia (an abnormality of red blood cells), multiple myeloma (cancer of the bone marrow), or leukemia (cancer of the blood cells))

§ problems with blood clotting (hemophilia)

§ diseases accompanied by bleeding

§ exacerbation of gastric ulcer or duodenum

§ Simultaneous administration with drugs of the alpha-adrenergic blocking group

According to the registered indication, the drug is not intended for use in children and adolescents under the age of 18 years and in women.

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Drug Interactions

Effect of other medicinal products on sildenafil

In vivo studies

At simultaneous reception sildenafil with CYP3A4 inhibitors (such as ketoconazole, erythromycin and cimetidine) there is a decrease in the clearance of sildenafil. In this group of patients, there is no increased frequency side effects However, it is necessary to start treatment with Viagra® at an initial dose of 25 mg.

Simultaneous administration of the HIV protease inhibitor ritonavir, which is a strong inhibitor of cytochrome P450, in an equilibrium state (500 mg twice a day) with sildenafil (100 mg single dose) leads to an increase in the maximum concentration (Cmax) of sildenafil by 300% (4-fold), as well as an increase in plasma AUC of sildenafil by 1000% (11-fold). After 24 hours, plasma levels of sildenafil are approximately 200 ng/mL compared to approximately 5 ng/mL after sildenafil alone. These data are consistent with the pronounced effects of ritonavir on wide range cytochrome P450 substrates. Based on the above data, the concomitant use of sildenafil with ritonavir is not recommended.

Viagra does not affect the pharmacokinetics of ritonavir.

The maximum dose of sildenafil should not, under any circumstances, exceed 25 mg in 48 hours.

Simultaneous administration of the HIV protease inhibitor saquinavir, which is an inhibitor of CYP3A4, in an equilibrium state (1200 mg three times a day) with sildenafil (100 mg single dose) leads to an increase in Cmax of sildenafil by 140%, as well as an increase in AUC of sildenafil by 210%. Sildenafil does not affect the pharmacokinetics of saquinavir. Stronger CYP3A4 inhibitors, such as ketoconazole and itraconazole, have a more pronounced effect.

With a single dose of sildenafil at a dose of 100 mg together with erythromycin, a moderate inhibitor of CYP3A4, at steady state (500 mg twice a day for 5 days), there is an increase in systemic exposure of sildenafil by 182% (determined by the value of AUC).

Azithromycin (at a dose of 500 mg per day for 3 days) does not affect the AUC, Cmax, Tmax, elimination rate constant or subsequent half-life of sildenafil or its main circulating metabolite.

The simultaneous use of cimetidine (800 mg), which is an inhibitor of cytochrome P450 and a non-specific inhibitor of CYP3A4 with sildenafil (at a dose of 50 mg) in healthy volunteers, causes an increase in plasma concentrations of sildenafil by 56%.

Grapefruit juice is a weak inhibitor of CYP3A4-mediated metabolism in the intestinal wall and may cause a moderate increase in plasma levels of sildenafil.

A single dose of an antacid (magnesium hydroxide / aluminum hydroxide) does not affect the bioavailability of sildenafil.

CYP2C9 inhibitors (tolbutamide, warfarin and phenytoin), CYP2D6 inhibitors (selective serotonin reuptake inhibitors, tricyclic antidepressants), thiazide and thiazide-like diuretics, loop and potassium-sparing diuretics, angiotensin converting enzyme (ACE) inhibitors, blockers calcium channels, blockers of beta-adrenergic receptors and inducers of metabolic activity P450 (rifampicin, barbiturates) do not affect the pharmacokinetics of sildenafil.

Co-administration of the endothelin antagonist bosentan (a moderate inducer of CYP3A4, CYP2C9 and probably CYP2C19) at steady state (125 mg twice daily) with sildenafil at steady state (80 mg three times daily) resulted in a decrease in AUC and Cmax for sildenafil by 62.6% and 55.4% respectively. Thus, it is believed that simultaneous use with strong CYP3A4 inducers, such as rifampin, causes a more pronounced decrease in plasma concentrations of sildenafil.

Simultaneous use with other PDE-5 inhibitors or other treatments for erectile dysfunction

The safety and efficacy of sildenafil in combination with other PDE-5 inhibitors or other medicinal products containing sildenafil for the treatment of pulmonary arterial hypertension (PAH) or other drugs for the treatment of erectile dysfunction have not been studied. In this regard, the use of such combinations of drugs is not recommended.

Nicorandil is a hybrid of a potassium channel activator and nitrate. Due to the nitrate component, it is potentially capable of entering into serious interactions with sildenafil.

Effect of sildenafil on other medicinal products

In vitro studies

Data on the interaction of sildenafil with non-specific phosphodiesterase inhibitors, such as theophylline or dipyridamole, are not available.

In vivo studies

According to the known action of sildenafil on signaling pathway NO / cGMP, sildenafil is capable of enhancing the hypotensive effect of nitrates, namely, a significant decrease blood pressure. Therefore, its simultaneous use with nitric oxide donors (amyl nitrite) or nitrates in any form is contraindicated.

Riociguat

IN clinical research riociguat enhanced the hypotensive effect of PDE-5 inhibitors. Data on a favorable clinical effect with the use of this combination in the studied population were absent. The simultaneous use of riociguat with PDE-5 inhibitors, including sildenafil, is contraindicated.

Simultaneous reception with alpha-blockers

It is recommended to use sildenafil with caution in patients taking a drug of the alpha-blocker group, since their simultaneous use can lead to symptomatic arterial hypotension in some sensitive patients. Most likely, this can be observed within 4 hours after taking a dose of sildenafil. To reduce the risk of developing postural arterial hypotension, a state of hemodynamic stability should be achieved in patients receiving treatment with alpha-blockers before starting treatment with sildenafil. The possibility of using sildenafil should be considered, starting with a dose of 25 mg. In addition, clinicians should instruct patients on what to do if symptoms of postural hypotension occur.

With the simultaneous use of sildenafil and doxazosin in patients stabilized with doxazosin therapy, rare cases of symptomatic arterial hypotension, dizziness and presyncope, but not syncope, have been reported.

With the simultaneous use of sildenafil (at a dose of 50 mg) with tolbutamide (at a dose of 250 mg) or warfarin (at a dose of 40 mg), both of which are metabolized by CYP2C9, no significant interactions were found.

Sildenafil (at a dose of 50 mg) does not increase the bleeding time caused by taking acetylsalicylic acid(at a dose of 150 mg).

Sildenafil (at a dose of 50 mg) does not increase the hypotensive effect of alcohol in healthy volunteers at an average maximum blood alcohol level of 80 mg / dl.

Combining the following classes of antihypertensives medicines: diuretics, beta-blockers, ACE inhibitors, angiotensin II antagonists, antihypertensive drugs (vasodilators and central action), adrenergic neuroblockers, calcium channel blockers and alpha-adrenergic blockers - did not reveal a difference in the side effect profile in patients taking sildenafil compared with patients receiving placebo. In special drug interaction studies in which sildenafil (at a dose of 100 mg) was used simultaneously with amlodipine in patients with arterial hypertension, an additional decrease in systolic blood pressure in the supine position was 8 mm. rt. Art. The corresponding additional reduction in diastolic blood pressure in the supine position was 7 mm. rt. Art. These additional blood pressure reductions were similar in magnitude to those observed when sildenafil was used in healthy volunteers as monotherapy.

Sildenafil (at a dose of 100 mg) does not affect the pharmacokinetics at steady state of the HIV protease inhibitors saquinavir and ritonavir, both of which are CYP3A4 substrates.

When used simultaneously with bosentan, sildenafil at steady state (80 mg three times a day) causes an increase in the AUC and Cmax of bosentan (125 mg twice a day) by 49.8% and 42%, respectively, in healthy male volunteers.

special instructions"type="checkbox">

special instructions

To diagnose erectile dysfunction and determine its possible underlying causes, a medical history and physical examination should be performed before pharmacological treatment is considered.

Risk factors for cardiovascular disease

Before starting treatment for erectile dysfunction, the attending physician should assess the cardiovascular status of their patients, since there is a certain degree of risk of cardiac complications associated with sexual activity.

Before prescribing sildenafil, physicians should carefully consider the possibility of adverse effects of the vasodilating effect of this drug on the condition of patients with certain underlying diseases, especially in combination with sexual activity. The group of hypersensitivity to vasodilators includes patients with left ventricular outflow tract narrowing (for example, aortic valve stenosis, hypertrophic obstructive cardiomyopathy), as well as patients with a rare multiple system atrophy syndrome, manifested as a severe degree of impaired autonomic control of blood pressure.

Sildenafil leads to a slight and short-term decrease in blood pressure, which in most cases does not clinical manifestations. The average maximum decrease in systolic blood pressure in the supine position after oral administration of sildenafil at a dose of 100 mg was 8.4 mm Hg. Art. The corresponding change in diastolic blood pressure in the supine position was 5.5 mm. rt. Art. These reductions in blood pressure are consistent with the vasodilatory effects of sildenafil, possibly due to increased levels of cGMP in smooth muscles vessels. A single oral dose of sildenafil up to 100 mg in healthy volunteers did not cause any clinical significant changes on the ECG.

In patients with severe coronary disease heart disease (IHD), sildenafil at a dose of 100 mg did not affect cardiac output and did not reduce blood flow through stenotic coronary arteries.

Viagra® enhances the hypotensive effect of nitrates.

In accordance with the action of Viagra® on the metabolic pathway "nitric oxide / cyclic guanosine monophosphate (cGMP)", sildenafil is capable of enhancing the hypotensive effect of nitrates, therefore its simultaneous use with nitric oxide donators (such as amyl nitrite) or nitrates is contraindicated in any form.

Serious cardiovascular events have been reported during the post-marketing period, including myocardial infarction, unstable angina, sudden cardiac death, ventricular arrhythmia, cerebrovascular bleeding, transient ischemic attack, hypertension, and arterial hypotension during the use of sildenafil. Most, but not all, of these patients had prior cardiovascular risk factors. Many of these events have been reported during or shortly after sexual intercourse, and several have been reported shortly after taking sildenafil without sexual activity. It is not possible to determine whether these events were directly related to the intake of sildenafil, to sexual activity, to existing cardiovascular disease, to a combination of these factors, or to other factors.

Priapism

Drugs for the treatment of erectile dysfunction, including sildenafil, should be used with caution in patients with an anatomical deformity of the penis (such as angulation, cavernous fibrosis, or Peyronie's disease), as well as in patients with diseases predisposing to the development of priapism (such as falciform cell anemia, multiple myeloma, or leukemia).

During the post-registration use of sildenafil, cases of prolonged erection and priapism have been reported. In the event of an erection lasting more than 4 hours, the patient should seek urgent medical care. With absence emergency treatment priapism can lead to damage to the tissues of the penis and irreversible loss of potency.

Impact on vision

There have been cases of visual impairment in connection with the intake of sildenafil and other PDE-5 inhibitors, namely a rare disease - anterior non-arteritic ischemic optic neuropathy. In case of any defects in visual acuity, you must stop taking Viagra® and consult a doctor.

Effect on blood clotting

In vitro studies using human platelets indicate that sildenafil enhances the antiplatelet effect of sodium nitroprusside. There are no data on the safety of sildenafil in patients with bleeding disorders or active peptic ulcer, so sildenafil should be used after a careful assessment of the benefit/risk ratio.

Viagra should not be used in men with rare hereditary galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption syndrome, due to the lactose content in the drug shell.

Pregnancy and lactation

Viagra® is not indicated for use by women.

Appropriate and strictly controlled studies of the use of Viagra® in pregnant and lactating women have not been conducted.

reproductive function

The effect of the drug on sperm motility or morphology after a single oral dose of sildenafil at a dose of 100 mg was not found.

Features of influence medicinal product on the ability to drive a motor vehicle or potentially dangerous machinery

The effect of sildenafil on the ability to drive vehicles or operate potentially dangerous machinery has not been studied.

Before driving vehicles or working with mechanisms, patients should find out how their body reacts to taking Viagra®, due to side effects of the drug, such as dizziness and impaired visual perception.

Overdose

Adverse reactions reported in studies with a single dose of the drug at a dose of up to 800 mg with the participation of volunteers were comparable to those observed with lower doses of the drug, but the frequency of their occurrence and severity were higher. Taking higher doses of Viagra® (200 mg) does not lead to an increase in the effectiveness of the drug, but only to an increase in the frequency adverse reactions (headache, hyperemia, dizziness, dyspepsia, nasal congestion and impaired visual perception).

Shelf life

Do not use after the expiration date.

Terms of dispensing from pharmacies

On prescription

Manufacturer

Fareva Amboise,

Industriale Zone -29 Route des Industries

37530 Poce-sur-Cisse, France

Viagra - pills, the action of which is aimed at the natural sexual arousal in men. The drug is commonly used to eliminate erectile dysfunction. Active substance sildenafil tablets cause increased blood circulation in the genital area, resulting in increased and prolonged erection, as well as orgasmic experiences. Today in pharmacies under this name there are dietary supplements with natural ingredients, drugs to enhance libido and other means.

Viagra for men appeared on sale in 1998 and was intended to treat problems associated with potency. However, the drug was developed for completely different purposes. Initially, it was proposed to be used for patients with hypertension. But as it turned out during the study, he does not reduce pressure, but the men noted that after taking the pills they had a long erection.

More about pills for male strength, urologist Iskander Abdullin:

Later, the same effect was confirmed by other men. Therefore, it was decided to use the drug as a remedy for sexual impotence.

Over time, other manufacturers began to produce analogues (generics), which are still not always able to give the same effect that occurs after using Viagra.

The action of Viagra

How does Viagra work? The use of these tablets for men increases blood circulation in the penis. This is precisely what main secret the effectiveness of the drug, since it is the violation of blood flow to the organ that can cause a lack of erection.

There is an opinion that after taking the pill, the erection will last a very long time. However, this is not quite true. The fact is that the action of Viagra begins only when a man is sexually aroused. If earlier he had arousal, but the erection was absent or was insignificant, then after using the drug, the penis reaches its natural size and the hardness necessary for sexual intercourse. Thanks to the pills, sexual intercourse is lengthened (), but after ejaculation, the erection disappears and can only occur when the man is re-excited. The duration of Viagra is about 4 hours, which will be enough for several full-fledged sexual acts.

Some "insurance" for a man is that the pill starts to act only under the condition of natural arousal, that is, it cannot start working at an inconvenient moment for this. In addition, a woman will not be able to suspect a man of using the drug.

It is important to note that the effect of the use of the drug may decrease if a large amount of alcohol is consumed. At the same time, the effect of Viagra will be stronger with moderate food intake.

Time of action

Those who decide to use this drug are interested in the question: “How long does the pill work”? The effect of the use of "Viagra" can be seen on average 15-60 minutes after ingestion. Although for some men this figure may vary. Knowing when Viagra starts to work and how long Viagra lasts, a man can schedule her intake in time.

Indications for use

The maximum daily dose of the drug for a healthy man is 100 mg. You need to start using tablets with 50 mg. For certain groups of patients (men over 65 years of age, patients with pathology of the kidneys, liver or cardiovascular system), this dosage is reduced to 25 mg. How to take Viagra correctly can tell the doctor after a detailed examination of the man. Do not exceed the dose recommended by your doctor.

How to take medication for the treatment of erectile disorders? This question will be answered by the host of the program “Live is great!” Elena Malysheva and Professor, Doctor of Medical Sciences, Director of the University Clinic of Lomonosov Moscow State University Kamalov Armais Albertovich:

How to take Viagra? Taking into account the principle of action of Viagra, it is recommended to drink the pill with a sufficient amount of water, which will reduce the time of its penetration into the blood. If you take the drug during a plentiful feast, then the effect of it can be reduced, since food, especially fatty foods, prevents its absorption.

Contraindications

Like all drugs, Viagra has its own contraindications for use. All of them are due to the possibility of side effects of the drug in the presence of certain diseases. Viagra contraindications are:

1. Hypersensitivity to the components that make up Viagra.
2. Reception of any means, which contain nitrates. According to studies, their simultaneous use can lead to a sharp decrease in pressure in a man.
3. Severe disorders in the liver.

1. Medicines with PDE-5 inhibitors. The ban on their simultaneous use is associated with the lack of clinical trials and the inability to predict the effect of tablets in this case.
2. Age up to 18 years.

According to the instructions, there are a number of conditions in which taking pills is allowed only under medical supervision and with extreme caution:

• Features of the anatomy of the penis, which can be both congenital and acquired, in which blood circulation in the penis can be impaired. In such a situation, the effect of the drug cannot be predicted.
• Pathologies associated with priapism (involuntary erection for several hours without prior sexual stimulation).

• Leukemia.
• thrombocytemia.

Blood leukemia is a tumor of the hematopoietic system that primarily affects the hematopoietic cells of the bone marrow.

• Myeloma.
• Genetic determination of retinol.
• Exacerbation of peptic ulcer.
• Pathology of the heart and other disorders in the work of the organ that were observed in a man in the past. Male Viagra and other arousal stimulants are not recommended for those who have had a heart attack, stroke or angina pectoris.

Even a single dose of the drug is possible only after consulting a doctor. The above list of contraindications is far from complete. Side effects of "Viagra" can occur when used simultaneously with other medicines.

Indications for use, contraindications and methods of using Viagra and its analogues are very similar. Do not rely on the reviews of other people who have taken them, as this can lead to negative consequences. Before you start using this or that drug, you should consult your doctor.

Possible Complications

The dosage of the drug affects the possibility of side effects. Exploring possible harm"Viagra", doctors have identified a number of side effects:

1. Redness of the skin associated with increased blood circulation.
2. Headache.
3. visual impairment ( hypersensitivity to bright light, haze, etc.).

Candidate of Medical Sciences Elena Ivanovna Adamenko will talk about what dyspepsia is:

1. Dizziness.
2. increased frequency heart rate.
3. Dyspepsia.

1. Nasal congestion.
2. Seizures.
3. Arrhythmia.

Arrhythmia - any disturbance of the regularity or frequency of the normal heart rhythm, as well as the electrical conduction of the heart

1. Nose bleed.
2. Fainting.
3. A sharp drop in blood pressure.

Overdose

If you use Viagra for potency in high doses, you may experience unpleasant symptoms:

• From the side of the cardiovascular system: redness skin, headache, dizziness, nosebleeds, tachycardia.
• From the side digestive system: indigestion.
• Seizures.

Arsen Tonyan - urologist-andrologist, candidate of medical sciences will talk about the action of Viagra:

In order to prevent their occurrence, it is important for a man to know how often Viagra can be taken and at what dose.

viagra gel

To restore erectile function in men, you can use not only tablets, but also a preparation in the form of a gel. "Viagra gel" has the same composition and properties, but due to the gel form, it starts to act faster. Therefore, it can be considered an effective alternative to the known means.

Price

Any drugs intended to increase the potency of a man can only be bought at a pharmacy. You don't need a prescription for Viagra.

The cost of Viagra in a pharmacy may vary. Basically, its price depends on the manufacturer.

Table 1. The cost of "Viagra"

Remedy at home

Since Viagra is quite expensive and has many contraindications, the question arises: “Is it possible to replace it with something”? It turns out that at home you can prepare a remedy that will be no less effective. Since this alternative to Viagra is made on the basis of natural ingredients, it is suitable for almost all men and does not cause unpleasant consequences.

To prepare such products, you can use products - aphrodisiacs, which can naturally increase male potency. Among them:

1. Black chocolate.
2. Natural coffe.
3. Beekeeping products.
4. Bananas.
5. Nuts.
6. Strawberry.
7. Seafood, especially mussels, oysters, caviar and shrimp.

Dear readers, in this video we will talk about products to improve erection in men:

1. Ginseng.
2. Olive oil.
3. Garlic.
4. Celery.
5. Horseradish.
6. Asparagus.
7. Dill.

Of course, they will not lead to an instant reaction, but if you include most of these products in your diet, then soon a man will not need any potency stimulants.

Watermelon remedy

"Viagra" at home can be made from ordinary watermelon. For this you need:

• Wash a ripe watermelon and carefully cut off its rind, leaving the white part on the pulp.
• Cut the berry into pieces and squeeze the juice with a juicer or blender.
• Place 1 liter of squeezed juice in a saucepan and boil.

Preparation of "Homemade" Viagra from watermelon and lemon juice

• Add the squeezed juice from 1 lemon to the boiled liquid.
• Evaporate half of the liquid over very low heat.
• After cooling, send the liquid to the refrigerator.

Every morning you should drink a few tablespoons of the medicine received.

nettle recipe

A product based on dried fruits and fresh nettles has a good effect. To prepare it, you need to take:

1. 50 g nettle.
2. 1 cup boiling water.
3. Honey to taste.

Pour chopped nettles in a thermos with boiling water. After 30 minutes, strain the liquid and mix with natural honey. To make the effect even better, before drinking the medicine, you need to take a few sips of red wine or natural pomegranate juice.

The use of dried fruits

Useful and effective remedy can be made with dried fruits. This will require:

• Dried apricots.
• Prunes.
• Nuts.
• Raisin.
• Figs.

All components are taken in the same amount (250 g each). They must be crushed using a mortar. Every day, a man needs to eat 2 tablespoons of such a mixture, washed down with kefir.

Natural juices are no less effective: carrot, cucumber and beetroot. It is recommended to mix them in equal proportions and drink before meals.

The photo shows a crushed mixture of dried fruits.

Viagra is recognized as a fairly effective drug that helps improve erection. But what happens if an absolutely healthy man drinks it? It turns out that nothing will happen. If a man has a good erection, then it is unlikely to improve it. But if it is slightly reduced as a result of fatigue, stress or another reason, then the effect of the pill will definitely be.

Male power has always been the pride of any member of the stronger sex. But, for various reasons, it can worsen. In this case, various medical preparations, one of which is Viagra. It is recommended to buy it exclusively in a pharmacy, where the tablets have everything Required documents. But before doing this, it is important to consult a doctor. The doctor will help not only choose the required dose of medication, but also check if the patient has any contraindications to its use.

Drug for the treatment of erectile dysfunction. PDE-5 inhibitor

Active substance

Release form, composition and packaging

Orally dispersible tablets blue, diamond-shaped, engraved with "V50" on one side and smooth on the other side.

Excipients: ludiflash - 343.525 mg (302.3 mg, crospovidone ~ 17.18 mg, polyvinyl acetate ~ 16.32 mg, povidone ~ 1.46 mg), croscarmellose sodium - 25 mg, microcrystalline cellulose - 25 mg, colloidal silicon dioxide - 3.75 mg, sucralose - 5 mg , (30-36%) - 2.5 mg, sweetener (Sweetness Enhancer) - 5 mg (maltodextrin ~ 3.565 mg, flavor ~ 0.79 mg, dextrin ~ 0.395 mg, residual water ~ 0.25 mg), natural flavor (Natural Special) - 5 mg (maltodextrin ~ 4.3 mg, propylene glycol ~ 0.185 mg, glycerol ~ 0.18 mg, flavor ~ 0.085 mg, residual water ~ 0.25 mg), lemon flavor (Lemon Flavor) - 5 mg (maltodextrin ~ 4 mg, flavor ~ 0.75 mg, α -tocopherol ~ 0.0003 mg, residual water ~ 0.25 mg), magnesium stearate - 10 mg.

4 things. - blisters (1) - packs of cardboard with the control of the first opening.

pharmachologic effect

Sildenafil is a potent selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5).

The implementation of the physiological mechanism of erection is associated with the release of nitric oxide (NO) in the cavernous body during sexual stimulation. This, in turn, leads to an increase in the level of cGMP, subsequent relaxation of the smooth muscle tissue of the cavernous body and an increase in blood flow.

Sildenafil does not have a direct relaxing effect on the isolated human corpus cavernosum, but enhances the effect of NO through inhibition of PDE5, which is responsible for the breakdown of cGMP.

Sildenafil is selective for PDE5 in vitro, its activity against PDE5 exceeds activity against other known phosphodiesterase isoenzymes: PDE6 - 10 times; PDE1 - more than 80 times; PDE2, PDE4, PDE7-PDE11 - more than 700 times. Sildenafil is 4000 times more selective for PDE5 compared to PDEZ, which is of great importance, since PDEZ is one of the key enzymes in the regulation of myocardial contractility.

A prerequisite for the effectiveness of sildenafil is sexual stimulation. Sildenafil restores impaired erectile function under conditions of sexual stimulation by increasing blood flow to the cavernous bodies of the penis.

Clinical Data

Cardiac research

The use of sildenafil in doses up to 100 mg did not lead to clinically significant ECG changes in healthy volunteers. The maximum decrease in systolic blood pressure in the supine position after taking sildenafil at a dose of 100 mg was 8.3 mm Hg, and diastolic blood pressure - 5.3 mm Hg. A more pronounced, but also transient effect on blood pressure was noted in patients taking nitrates.

In a study of the hemodynamic effect of sildenafil at a single dose of 100 mg in 14 patients with severe CAD (more than 70% of patients had stenosis of at least one coronary artery), resting systolic and diastolic pressures decreased by 7% and 6%, respectively. , and pulmonary systolic pressure decreased by 9%. Sildenafil did not affect the ejection and did not impair blood flow in stenosed patients. coronary arteries, and also led to an increase (about 13%) of adenosine-induced coronary flow in both stenotic and intact coronary arteries.

In a double-blind, placebo-controlled study, 144 patients with erectile dysfunction and stable angina who were taking antianginal drugs (except nitrates) performed physical exercise until the severity of symptoms of angina decreased. The duration of the exercise was significantly longer (19.9 seconds; 0.9-38.9 seconds) in patients taking sildenafil at a single dose of 100 mg compared with patients receiving placebo.

In a randomized, double-blind, placebo-controlled study, the effect of changing the dose of sildenafil (up to 100 mg) was studied in men (n=568) with erectile dysfunction and arterial hypertension taking more than two. Sildenafil improved erections in 71% of men compared to 18% in the placebo group. The frequency of adverse effects was comparable to that in other groups of patients, as well as in individuals taking more sin of antihypertensive drugs.

Research on visual impairment

In some patients, 1 hour after taking sildenafil at a dose of 100 mg using the Farnsworth-Munsel 100 test, a mild and transient impairment in the ability to distinguish shades of color (blue / green) was detected. 2 hours after taking the drug, these changes were absent. It is believed that the violation of color vision is caused by inhibition of PDE6, which is involved in the process of light transmission in the retina. Sildenafil had no effect on visual acuity, contrast perception, electroretinogram, intraocular pressure or pupil diameter.

In a placebo-controlled crossover study of patients with proven early age-related macular degeneration (n=9), sildenafil at a single dose of 100 mg was well tolerated. There were no clinically significant visual changes assessed by specific visual tests (visual acuity, Amsler grating, color perception, color passage simulation, Humphrey perimeter, and photostress).

Efficiency

The efficacy and safety of sildenafil was evaluated in 21 randomized, double-blind, placebo-controlled studies lasting up to 6 months in 3000 patients aged 19 to 87 years with erectile dysfunction of various etiologies (organic, psychogenic or mixed). The effectiveness of the drug was assessed globally using an erection diary, an international index of erectile function (a validated questionnaire on the state of sexual function) and a partner survey.

The effectiveness of sildenafil, defined as the ability to achieve and maintain an erection sufficient for satisfactory intercourse, has been demonstrated in all studies conducted and has been confirmed in long-term studies lasting 1 year. In fixed dose studies, the ratio of patients reporting that the therapy improved their erections was: 62% (sildenafil 25 mg dose), 74% (sildenafil 50 mg dose) and 82% (sildenafil 100 mg dose), compared with 25 % in the placebo group. An analysis of the international index of erectile function showed that, in addition to improving erection, treatment with sildenafil also increased the quality of orgasm, made it possible to achieve satisfaction from sexual intercourse and overall satisfaction.

According to the pooled data, among patients who reported improvement in erection during treatment with sildenafil, there were 59% of patients diabetes, 43% of patients undergoing radical prostatectomy and 83% of patients with injuries spinal cord(compared to 16%, 15% and 12% in the placebo group, respectively).

Pharmacokinetics

Suction

Sildenafil is rapidly absorbed after oral administration. Absolute bioavailability averages 40% (25-63%). In vitro, sildenafil at a concentration of approximately 1.7 ng / ml (3.5 nM) inhibits human PDE5 by 50%. After a single dose of sildenafil at a dose of 100 mg, the average Cmax of free sildenafil in the blood is 18 ng / ml (38 nM) and is achieved when taken on an empty stomach for an average of 60 minutes (30-120 minutes).

When taken in combination with fatty foods, the rate of absorption is reduced; C max decreases by an average of 29%, T max increases by 60 minutes. However, the degree of absorption does not change significantly (AUC decreases by 11%).

Distribution

V d of sildenafil in the equilibrium state averages 105 liters. The binding of sildenafil and its main circulating N-demethyl metabolite to plasma proteins is about 96% and does not depend on the total concentration of sildenafil. Less than 0.0002% of the dose (mean 188 ng) was found in semen 90 minutes after taking the drug.

Metabolism

Sildenafil is metabolized mainly in the liver by the action of CYP3A4 isoenzymes (major pathway) and CYP2C9 (minor pathway). The main circulating active metabolite, which is formed as a result of N-demethylation of sildenafil, undergoes further metabolism. In terms of selectivity of action on PDE, the metabolite is comparable to sildenafil, and its activity against PDE5 in vitro is approximately 50% of the activity of sildenafil. The concentration of the metabolite in plasma is approximately 40% of the concentration of sildenafil. The N-demethyl metabolite undergoes further metabolism; its T 1/2 is about 4 hours.

breeding

The total clearance of sildenafil is 41 l / h, and the final T 1/2 is 3-5 hours. After oral administration, as well as after intravenous administration, sildenafil is excreted as metabolites, mainly with feces (approximately 80% of the dose) and to a lesser extent - with urine (about 13% of the dose).

Pharmacokinetics in special clinical situations

In healthy elderly people (over 65 years), the clearance of sildenafil is reduced, and the concentration of free active substance in plasma, approximately 40% higher than its concentration in young (18-45 years) patients. Age does not have a clinically significant effect on the incidence of side effects.

With mild renal failure (CC 50-80 ml / min) and moderate (CC 30-49 ml / min) severity, the pharmacokinetic parameters of sildenafil after a single oral dose of 50 mg do not change. In severe renal insufficiency (CC ≤30 ml / min), the clearance of sildenafil is reduced, which leads to an approximately twofold increase in AUC (100%) and C max (88%) compared with those with normal renal function in patients of the same age group .

In patients with cirrhosis of the liver (class A and B on the Child-Pugh scale), the clearance of sildenafil is reduced, which leads to an increase in AUC (84%) and C max (47%) compared with those in normal liver function in patients of the same age group. The pharmacokinetics of sildenafil in patients with severe hepatic impairment (Child-Pugh class C) has not been studied.

Indications

• treatment of erectile dysfunction characterized by an inability to achieve or maintain an erection of the penis sufficient for satisfactory intercourse.

Sildenafil is only effective with sexual stimulation.

Contraindications

• severe liver failure (Child-Pugh class C);
• severe cardiovascular diseases (severe heart failure, unstable angina pectoris, stroke or myocardial infarction in the last 6 months, life-threatening arrhythmias, arterial hypertension(BP >170/100 mmHg) or hypotension (BP<90/50 мм рт.ст.));
• episodes of development of non-arteritic anterior ischemic optic neuropathy with loss of vision in one eye;
• hereditary retinitis pigmentosa;
• use in patients receiving constantly or intermittently nitric oxide donators, organic nitrates or nitrites in any form, since sildenafil enhances the hypotensive effect of nitrates;
• the combined use of PDE5 inhibitors, including sildenafil, with guanylate cyclase stimulants, such as riociguat, tk. this may lead to symptomatic hypotension;
• simultaneous use of the drug with other drugs for the treatment of erectile dysfunction (the safety and efficacy of combination therapy has not been studied);
• concomitant use of ritonavir;
• lactose intolerance, lactase deficiency, glucose-galactose malabsorption;
• children and adolescents up to 18 years of age;
• use in women;
• hypersensitivity to sildenafil or to any other component of the drug.

Carefully: anatomical deformation of the penis (angulation, cavernous fibrosis or Peyronie's disease); diseases predisposing to the development of priapism (sickle cell anemia, multiple myeloma, leukemia, thrombocythemia); diseases accompanied by bleeding; peptic ulcer of the stomach and duodenum in the acute phase; liver dysfunction; severe renal failure (CC less than 30 ml / min); an episode of the development of anterior non-arteritic ischemic neuropathy of the optic nerve in history; simultaneous reception of alpha-blockers.

Dosage

The drug is taken orally. The orodispersible tablets can be taken with or without water. You should put the tablet on the tongue, after which it will quickly dissolve and can be swallowed. The tablet should be taken immediately after opening the blister. For patients on a recommended dose of sildenafil 100 mg, the second sildenafil 50 mg tablet should be taken after the first sildenafil 50 mg tablet has completely dissolved.

It should be borne in mind that the absorption of sildenafil is significantly slowed down when it is used in combination with fatty foods.

For most patients, the recommended dose is 50 mg approximately 1 hour before sexual activity. Based on efficacy and tolerability, the dose may be increased to 100 mg or reduced to 25 mg (only film-coated tablets of the appropriate dosage should be taken).

The maximum recommended dose is 100 mg. The maximum recommended frequency of use is 1 time / day. Patients who are recommended a dose of sildenafil 100 mg should take two tablets, dispersed in the oral cavity with a dosage of 50 mg, sequentially one after the other.

At renal failure of mild to moderate severity (CC 30-80 ml / min) dose adjustment is not required when severe renal failure (CC<30 мл/мин) the dose of sildenafil should be reduced to 25 mg.

Since the excretion of sildenafil is impaired in patients with liver damage (eg, cirrhosis), the dose of the drug should be reduced to 25 mg.

At elderly patients dose adjustment is not required.

Combined use with other drugs

When combined with ritonavir, the maximum single dose of Viagra should not exceed 25 mg, the frequency of use should be 1 time in 48 hours.

When combined with inhibitors of the CYP3A4 isoenzyme (erythromycin, saquinavir, ketoconazole, itraconazole), the initial dose of Viagra should be 25 mg.

To minimize the risk of developing postural hypotension in patients taking alpha-blockers, the use of Viagra should be started only after hemodynamic stabilization has been achieved in these patients. The feasibility of reducing the initial dose of sildenafil should be considered.

Side effects

The most common side effects were headache and "hot flashes".

Side effects are usually mild or moderate and transient.

In studies using a fixed dose, it was found that the frequency of some adverse events increases with increasing dose.

The frequency of adverse reactions is defined as follows: very often (≥10%), often (≥1% and<10%), нечасто (≥0.1% и <1%), редко (≥0.01% и <0.1%), очень редко (<0.01%), частота неизвестна (невозможно определить на основе имеющихся данных).

From the immune system: infrequently - hypersensitivity reactions (including skin rash), allergic reactions.

From the side of the organ of vision: often - blurred vision, visual impairment, cyanopsia; infrequently - eye pain, photophobia, photopsia, chromatopsia, redness of the eyes / scleral injections, changes in the brightness of light perception, mydriasis, conjunctivitis, hemorrhage in the eye tissue, cataracts, disruption of the lacrimal apparatus; rarely - swelling of the eyelids and adjacent tissues, a feeling of dryness in the eyes, the presence of iridescent circles in the field of view around the light source, increased eye fatigue, seeing objects in yellow (xanthopsia), seeing objects in red (erythropsia), conjunctival hyperemia, irritation of the mucous membrane eye, discomfort in the eyes; frequency unknown - non-arteritic anterior ischemic optic neuropathy (NPINZN), retinal vein occlusion, visual field defect, diplopia *, temporary loss of vision or decreased visual acuity, increased intraocular pressure, retinal edema, retinal vascular disease, vitreous detachment / vitreal traction.

From the organ of hearing: infrequently - a sudden decrease or loss of hearing, tinnitus, ear pain.

From the side of the cardiovascular system: often - "tides"; infrequently - tachycardia, palpitations, decreased blood pressure, increased heart rate, unstable angina, AV blockade, myocardial ischemia, cerebral thrombosis, cardiac arrest, heart failure, abnormal ECG readings, cardiomyopathy; rarely - atrial fibrillation, sudden cardiac death *, ventricular arrhythmia *.

From the hematopoietic system: infrequently - anemia, leukopenia.

From the side of metabolism and nutrition: infrequently - a feeling of thirst, edema, gout, uncompensated diabetes mellitus, hyperglycemia, peripheral edema, hyperuricemia, hypoglycemia, hypernatremia.

From the respiratory system: often - nasal congestion; infrequently - epistaxis, rhinitis, asthma, dyspnea, laryngitis, pharyngitis, sinusitis, bronchitis, increased sputum volume, increased cough; rarely - a feeling of tightness in the throat, dryness of the nasal mucosa, swelling of the nasal mucosa.

From the digestive system: often - nausea, dyspepsia; infrequently - gastroesophageal reflux disease, vomiting, abdominal pain, dry mouth, glossitis, gingivitis, colitis, dysphagia, gastritis, gastroenteritis, esophagitis, stomatitis, abnormal liver function tests, rectal bleeding; rarely - hypoesthesia of the oral mucosa.

From the musculoskeletal system: often - back pain; infrequently - myalgia, pain in the extremities, arthritis, arthrosis, tendon rupture, tenosynovitis, bone pain, myasthenia gravis, synovitis.

From the genitourinary system: infrequently - cystitis, nocturia, breast enlargement, urinary incontinence, hematuria, ejaculation disorder, genital edema, anorgasmia, hematospermia, damage to the tissues of the penis; rarely - prolonged erection and / or priapism.

From the side of the central and peripheral nervous system: very often - headache; often - dizziness; infrequently - drowsiness, migraine, ataxia, hypertonicity, neuralgia, neuropathy, paresthesia, tremor, vertigo, symptoms of depression, insomnia, unusual dreams, increased reflexes, hypoesthesia; rarely - convulsions *, repeated convulsions *, fainting.

From the skin and subcutaneous tissues: infrequently - skin rash, urticaria, herpes simplex, pruritus, increased sweating, skin ulceration, contact dermatitis, exfoliative dermatitis; frequency unknown - Stevens-Johnson syndrome, toxic epidermal necrolysis.

Others: infrequently - a feeling of heat, swelling of the face, photosensitivity reactions, shock, asthenia, fatigue, pain of various localization, chills, accidental falls, chest pain, accidental injuries; rarely - irritability.

* Side effects identified during post-marketing studies.

During the post-marketing use of sildenafil for the treatment of erectile dysfunction, adverse events such as severe cardiovascular complications (including myocardial infarction, unstable angina, sudden cardiac death, ventricular arrhythmia, hemorrhagic stroke, transient ischemic attack, hypertension and hypotension) have been reported. ), which had a temporal relationship with the use of sildenafil. Most of these patients, but not all of them, had risk factors for cardiovascular complications. Many of these adverse events were observed shortly after sexual activity, and some of them were noted after taking sildenafil without subsequent sexual activity. It is not possible to establish the existence of a direct relationship between the observed adverse events and these or other factors.

Visual disturbances

In rare cases, during post-registration use of all PDE5 inhibitors, incl. sildenafil, reported non-arteritic anterior ischemic optic neuropathy (NPINZN) - a rare disease and the cause of reduced or loss of vision. Most of these patients had risk factors, in particular, a reduced cup-to-optic disc diameter ratio ("congestive disc"), age over 50 years, diabetes mellitus, hypertension, CAD, hyperlipidemia, and smoking. An observational study assessed whether recent use of drugs of the PDE5 inhibitor class is associated with acute onset of NPINZN. The results indicate an approximately two-fold increase in the risk of NPINZN within 5 half-lives after the use of a PDE5 inhibitor. According to published literature data, the annual incidence of NPINZN is 2.5-11.8 cases per 100,000 men aged ≥50 years in the general population. Patients should be advised in the event of sudden loss of vision to discontinue sildenafil therapy and consult a physician immediately. Individuals who have already had a case of NPNDI have an increased risk of recurrent NINZN. Therefore, the physician should discuss this risk with these patients and also discuss with them the potential for adverse effects of PDE5 inhibitors. PDE5 inhibitors, incl. Sildenafil should be used with caution in such patients and only in situations where the expected benefit outweighs the risk.

When using the drug Viagra in doses exceeding the recommended, adverse events were similar to those noted above, but usually occurred more often.

Overdose

With a single dose of Viagra at a dose of up to 800 mg, adverse events were comparable to those when taking the drug at lower doses, but were more common.

The use of the drug at a dose of 200 mg did not lead to an increase in the effectiveness of the drug, but the frequency of adverse reactions (headache, hot flashes, dizziness, dyspepsia, nasal congestion, visual impairment) increased.

Treatment: conducting symptomatic therapy. Hemodialysis does not accelerate the clearance of sildenafil, because the latter actively binds to plasma proteins and is not excreted in the urine.

drug interaction

Effect of other drugs on the metabolism of sildenafil

The metabolism of sildenafil occurs mainly in the liver under the action of CYP3A4 (the main route) and CYP2C9 isoenzymes, therefore inhibitors of these isoenzymes can reduce the clearance of sildenafil, and inducers, respectively, increase the clearance of sildenafil.

With the simultaneous use of CYP3A4 inhibitors (ketoconazole, erythromycin, cimetidine), a decrease in the clearance of sildenafil was noted.

Cimetidine (at a dose of 800 mg), which is a non-specific inhibitor of CYP3A4, when taken simultaneously with sildenafil (at a dose of 50 mg), causes an increase in plasma concentration of sildenafil by 56%.

A single dose of sildenafil at a dose of 100 mg simultaneously with erythromycin, a specific inhibitor of CYP3A4 (500 mg 2 times / day for 5 days) against the background of achieving a constant concentration of erythromycin in the blood, leads to an increase in the AUC of sildenafil by 182%.

With the simultaneous use of sildenafil (once at a dose of 100 mg) and saquinavir (at a dose of 1200 mg 3 times / day), which is both an inhibitor of HIV protease and an inhibitor of CYP3A4, while achieving a constant concentration of saquinavir in the blood, Cmax of sildenafil in the blood increased by 140% and AUC increased by 210%. Sildenafil did not affect the pharmacokinetic parameters of saquinavir.

Stronger inhibitors of the CYP3A4 isoenzyme, such as ketoconazole or itraconazole, can cause more pronounced changes in the pharmacokinetics of sildenafil.

The simultaneous use of sildenafil (once at a dose of 100 mg) and ritonavir (500 mg 2 times / day), which is an inhibitor of HIV protease and a strong inhibitor of cytochrome P450 isoenzymes, against the background of achieving a constant concentration of ritonavir in the blood, leads to an increase in Cmax of sildenafil by 300% (4 times), and AUC by 1000% (11 times). After 24 hours, the concentration of sildenafil in plasma was approximately 200 ng / ml (with a single application of one sildenafil - 5 ng / ml). This is consistent with the effect of ritonavir on a wide range of cytochrome P450 substrates. Sildenafil does not affect the pharmacokinetics of ritonavir. Given these data, the concomitant use of ritonavir and sildenafil is not recommended. In any case, the maximum dose of sildenafil should under no circumstances exceed 25 mg in 48 hours.

A single dose of an antacid (magnesium hydroxide / aluminum hydroxide) does not affect the bioavailability of sildenafil.

In studies involving healthy volunteers, the simultaneous use of an endothelin receptor antagonist, bosentan (an inducer of the CYP3A4 isoenzyme (moderate), CYP2C9 and possibly CYP2C19) at an equilibrium concentration (125 mg 2 times / day) and sildenafil at an equilibrium concentration (80 mg 3 times a day) /day) there was a decrease in AUC and Cmax of sildenafil by 62.6% and 52.4%, respectively. Sildenafil increased the AUC and Cmax of bosentan by 49.8% and 42%, respectively. It is assumed that the simultaneous use of sildenafil with potent inducers of the CYP3A4 isoenzyme, such as rifampicin, may lead to a greater decrease in the concentration of sildenafil in the blood plasma.

CYP2C9 isoenzyme inhibitors (such as tolbutamide, warfarin), CYP2D6 isoenzyme inhibitors (such as selective serotonin reuptake inhibitors, tricyclic antidepressants), thiazides and thiazide-like diuretics, ACE inhibitors and calcium antagonists do not affect the pharmacokinetics of sildenafil.

Simultaneous administration of azithromycin (500 mg / day for 3 days) does not affect AUC, C max , T max , excretion rate constant and T 1/2 of sildenafil or its main circulating metabolite.

Effect of sildenafil on other medicinal products

Sildenafil is a weak inhibitor of isoenzymes of the cytochrome P450 system - 1A2, 2C9, 2C19, 2D6, 2E1 and 3A4 (IK 50 > 150 μmol). When using sildenafil at recommended doses, its C max is about 1 μmol, so it is unlikely that sildenafil can affect the clearance of substrates of these isoenzymes.

Sildenafil enhances the hypotensive effect of nitrates both with long-term use and with acute indications. In this regard, the use of sildenafil in combination with nitrates or nitric oxide donators is contraindicated.

With the simultaneous administration of the alpha-blocker doxazosin (4 mg and 8 mg) and sildenafil (25 mg, 50 mg and 100 mg) in patients with benign prostatic hyperplasia with stable hemodynamics, the average additional reduction in systolic / diastolic blood pressure in the supine position was 7 /7 mmHg, 9/5 mmHg and 8/4 mm Hg. respectively, and in the standing position - 6/6 mm Hg, 11/4 mm Hg. and 4/5 mm Hg. respectively. Rare cases have been reported in these patients of symptomatic postural hypotension, manifested in the form of dizziness (without syncope). In selected sensitive patients receiving alpha-blockers, the simultaneous use of sildenafil may lead to symptomatic hypotension.

Signs of a significant interaction of sildenafil with tolbutamide (250 mg) or warfarin (40 mg), which are metabolized by CYP2C9, have not been identified.

Sildenafil at a dose of 100 mg does not affect the pharmacokinetic parameters of the HIV protease inhibitor saquinavir, which is a CYP3A4 substrate, at a constant concentration in the blood.

The simultaneous use of sildenafil in an equilibrium state (80 mg 3 times / day) leads to an increase in AUC and Cmax of bosentan (125 mg 2 times / day) by 49.8% and 42%, respectively.

Sildenafil at a dose of 50 mg does not cause an additional increase in bleeding time when taken at a dose of 150 mg.

Sildenafil at a dose of 50 mg does not enhance the hypotensive effect of ethanol in healthy volunteers with a maximum blood ethanol level of 0.08% (80 mg/dL) on average.

In patients with arterial hypertension, there were no signs of the interaction of sildenafil (at a dose of 100 mg) with amlodipine. The average additional decrease in blood pressure in the prone position is 8 mm Hg. (systolic) and 7 mm Hg. (diastolic).

The use of sildenafil in combination with antihypertensive agents does not lead to additional side effects.

special instructions

To diagnose erectile dysfunction, determine their possible causes and select adequate treatment, it is necessary to collect a complete medical history and conduct a thorough physical examination. Treatments for erectile dysfunction should be used with caution in patients with anatomical deformity of the penis (angulation, cavernous fibrosis, Peyronie's disease), or in patients with risk factors for developing priapism (sickle cell anemia, multiple myeloma, leukemia).

During post-marketing studies, cases of the development of prolonged erection and priapism have been reported. If an erection persists for more than 4 hours, the patient should immediately seek medical attention. If priapism therapy is not carried out immediately, this can lead to damage to the tissues of the penis and irreversible loss of potency.

Drugs intended for the treatment of erectile dysfunction should not be prescribed to men for whom sexual activity is undesirable.

Sexual activity poses a certain risk in the presence of heart disease, therefore, before starting any therapy for erectile dysfunction, the doctor should refer the patient to a cardiovascular examination. Sexual activity is undesirable in patients with heart failure, unstable angina, myocardial infarction or stroke in the last 6 months, life-threatening arrhythmias, arterial hypertension (BP > 170/100 mmHg), or hypotension (BP<90/50 мм рт.ст.). Прием силденафила у таких пациентов противопоказан. В клинических исследованиях показано отсутствие различий в частоте развития инфаркта миокарда (1.1 на 100 человек в год) или частоте смертности от сердечно-сосудистых заболеваний (0.3 на 100 человек в год) у пациентов, получавших препарат Виагра, по сравнению с пациентами, получавшими плацебо.

Cardiovascular Complications

Serious cardiovascular events (including myocardial infarction, unstable angina, sudden cardiac death, ventricular arrhythmia, hemorrhagic stroke, transient ischemic attack, arterial hypertension and hypotension) that had a temporal relationship with the use of sildenafil. Most of these patients, but not all of them, had risk factors for cardiovascular complications. Many of these adverse events were observed shortly after sexual activity, and some of them were noted after taking sildenafil without subsequent sexual activity. It is not possible to establish the existence of a direct relationship between the observed adverse events and these or other factors.

hypotension

Sildenafil has a systemic vasodilatory effect, leading to a transient decrease in blood pressure, which is not a clinically significant effect and does not lead to any consequences in most patients. However, before prescribing Viagra, the physician must carefully assess the risk of possible adverse manifestations of the vasodilating effect in patients with relevant diseases, especially against the background of sexual activity. Increased susceptibility to vasodilators is observed in patients with left ventricular outflow tract obstruction (aortic stenosis, hypertrophic obstructive cardiomyopathy), as well as in rare multiple system atrophy syndrome, manifested by severe dysregulation of blood pressure from the autonomic nervous system.

Since the combined use of sildenafil and alpha-blockers can lead to symptomatic hypotension in some sensitive patients, Viagra should be used with caution in patients taking alpha-blockers. To minimize the risk of postural hypotension in patients taking alpha-blockers, Viagra should be started only after stabilization of hemodynamic parameters in these patients. You should also consider the feasibility of reducing the initial dose of Viagra. Patients should be informed about what actions to take if symptoms of postural hypotension appear.

Visual disturbances

In rare cases, during post-registration use of all PDE5 inhibitors, incl. sildenafil, reported non-arteritic anterior ischemic optic neuropathy (NPINZN) - a rare disease and the cause of reduced or loss of vision. Most of these patients had risk factors, in particular, a reduced cup-to-optic disc diameter ratio ("congestive disc"), age over 50 years, diabetes mellitus, hypertension, CAD, hyperlipidemia, and smoking. An observational study assessed whether recent use of drugs of the PDE5 inhibitor class is associated with acute onset of NPINZN. The results indicate an approximately two-fold increase in the risk of NPINZN within 5 half-lives after the use of a PDE5 inhibitor. According to published literature data, the annual incidence of NPINZN is 2.5-11.8 cases per 100,000 men aged ≥50 years in the general population. Patients should be advised in the event of sudden loss of vision to discontinue sildenafil therapy and consult a physician immediately. Individuals who have already had a case of NPNDI have an increased risk of recurrent NINZN. Therefore, the physician should discuss this risk with these patients and also discuss with them the potential for adverse effects of PDE5 inhibitors. PDE5 inhibitors, incl. Sildenafil should be used with caution in such patients and only in situations where the expected benefit outweighs the risk. Sildenafil is contraindicated in patients with episodes of NPNZN with loss of vision in one eye.

A small number of patients with hereditary retinitis pigmentosa have genetically determined disorders of the functions of retinal phosphodiesterases. There is no information on the safety of using Viagra in patients with retinitis pigmentosa, so sildenafil should be used with caution.

Hearing disorders

Some post-marketing and clinical studies report cases of sudden worsening or loss of hearing associated with the use of all PDE5 inhibitors, including sildenafil. Most of these patients had risk factors for sudden worsening or loss of hearing. A causal relationship between the use of PDE5 inhibitors and sudden hearing impairment or hearing loss has not been established. In the event of a sudden deterioration in hearing or hearing loss while taking sildenafil, the patient should immediately consult a doctor.

Bleeding

Sildenafil enhances the antiplatelet effect of sodium nitroprusside, a nitric oxide donor, on human platelets in vitro. Data on the safety of the use of sildenafil in patients with a tendency to bleeding or exacerbation of gastric and duodenal ulcers are not available, so Viagra should be used with caution in these patients. The incidence of epistaxis in patients with pulmonary hypertension associated with diffuse connective tissue disease was higher (sildenafil 12.9%, placebo 0%) than in patients with primary pulmonary hypertension (sildenafil 3%, placebo 2.4%). Patients receiving sildenafil in combination with a vitamin K antagonist had a higher incidence of epistaxis (8.8%) than patients not taking a vitamin K antagonist (1.7%).

Use in conjunction with other treatments for erectile dysfunction

The safety and efficacy of Viagra in conjunction with other PDE5 inhibitors or other drugs for the treatment of pulmonary hypertension containing sildenafil (for example, Revacio), or other treatments for erectile dysfunction have not been studied, so the use of such combinations is not recommended.

Influence on the ability to drive vehicles and control mechanisms

Against the background of taking sildenafil, no negative effect on the ability to drive a car or other technical means was observed. However, since when taking sildenafil, dizziness, a decrease in blood pressure, the development of chromatopsia, blurred vision and other side effects are possible, care should be taken when driving vehicles and engaging in other potentially hazardous activities that require increased concentration and speed of psychomotor reactions. You should also carefully consider the individual effect of the drug in these situations, especially at the beginning of treatment and when changing the dosing regimen.

With caution, the drug should be prescribed for violations of liver function.

Use in the elderly

In elderly patients, dose adjustment is not required.

Terms of dispensing from pharmacies

The drug is dispensed by prescription.

Terms and conditions of storage

The drug should be stored out of the reach of children at a temperature not exceeding 30 ° C. Shelf life - 3 years. Do not use after the expiry date stated on the packaging.

It is unlikely that there will be at least one adult on the planet who does not know what Viagra is and what wonderful properties this drug has. This fact is surprising when you consider that the development of the drug occurred by accident as a result of research conducted to create a cure for heart disease. In just a couple of decades, Viagra has become the world's most famous treatment for erectile dysfunction and maintains its high position in the pharmaceutical market. The accidental creation of the drug forced manufacturers to conduct many clinical trials to make sure not only the high efficiency, but also the safety of using Viagra. And the successful results obtained as a result of them fully proved the high effectiveness of the drug even in people suffering from a large number of concomitant diseases.

Viagra in tablets

Viagra is available as tablets containing 25, 50 or 100 mg of sildenafil citrate. Most often you can find packages of 1, 2 or 4 pieces, but there are also large packages of 12 pieces. The appearance of the drug is difficult to confuse with anything else - these are small blue diamond-shaped tablets, numbered by the manufacturer.

The action of the drug is based on the inhibition of a specific phosphodiesterase, which helps to release nitric oxide. It is this substance that fully relaxes smooth muscles, which increases blood flow in the male genital organ, resulting in an erection. But by itself, the effect of taking Viagra does not occur. For men, sexual stimulation is also important. The absorption of the active substance into the blood occurs quite quickly. The average response time of the body to the drug is about an hour. The speed may decrease slightly if the drug is taken simultaneously with fatty foods, so it is recommended to follow a special diet to achieve maximum results.

The instruction states that indications for the appointment of Viagra are erectile dysfunction associated with insufficiency of the genital response as a result of organic, psychogenic or mixed causes. Taking the drug is contraindicated in several groups of patients:

• Persons taking nitric oxide donators, organic nitrates, nitrites.
• Persons taking other drugs to treat insufficiency of the genital response.
• Children until they reach the age of 18.
• Women.

In some cases, an individual reaction to the components of Viagra may become a contraindication, but most often this drug is well tolerated. Some caution in taking the drug should be observed with identified anatomical deformities of the penis, with certain blood diseases, bleeding, peptic ulcer, heart failure, myocardial infarction, stroke, and blood pressure disorders. All of these cases require additional consultation with a specialist before taking the drug.

The dosage of the drug depends on the general condition of the patient, but the average is 50 mg. In some situations, it can be reduced or increased. The tablets should be taken orally about an hour before the expected time of sexual activity with some water. Within one day, it is forbidden to use more than 100 mg of the active substance, and in the presence of kidney or liver diseases, this dosage should be significantly reduced.

There are a number of medicines, the joint intake of which with Viagra is undesirable or should be carried out after consultation with a specialist. Among them are ritonavir, erythromycin, saquinavir, ketoconazole, itraconazole, alpha-blockers.

Side effects caused by taking the drug are quite rare, but among the possible ones one can distinguish: headache, blurred consciousness, blurred vision, "hot flashes", nasal congestion, nausea, dyspepsia, back pain, dizziness and some other undesirable symptoms. It should be remembered that the use of the drug in larger dosages than allowed per day, the likelihood of side effects increases many times. If an overdose or unwanted symptoms still occur, the patient is required to prescribe symptomatic treatment.

Special instructions for taking Viagra:

• Before prescribing a drug, the most thorough examination should be carried out to determine the primary cause of erectile dysfunction. This will allow more effective treatment to be prescribed.
• In rare cases, the result of taking the drug may be a priapism reaction. In cases where the reaction does not subside after 4 hours after taking the tablets, the patient is advised to seek medical help in order to avoid serious damage to the penis and complete loss of erection in the future.
• If a man, due to any circumstances, should avoid sexual activity, Viagra should not be prescribed to him.
• Increased sexual activity can become a factor in the development of cardiovascular diseases, so the patient must undergo the necessary examination and take tests before he starts taking the drug. This rule does not depend on the age of the patient.

Ingredients of Viagra

As mentioned earlier, the basis of the drug is sildenafil. It was created as a tool that can increase blood flow in the myocardium, but the result is a drug that significantly increases the blood flow to the pelvic organs. At its core, sildenafil is a selective inhibitor of cGMP-specific PDE-5. It is this fact that makes Viagra truly effective in the treatment of erectile dysfunction.

In addition to sildenafil, the drug contains cellulose, calcium hydrogen phosphate, croscarmellose sodium, magnesium stearate. Each of these substances in itself can cause a sensitive reaction of the body, but their content in tablets is so small that this happens extremely rarely.

How does Viagra work?

As mentioned earlier, Viagra inhibits a specific enzyme that specializes in ensuring the breakdown of cGMP in the cavernous body of the male penis. This results in a stronger release of nitric oxide during sexual stimulation. The smooth muscles of the cavernous body relax, the vessels expand and a large amount of blood begins to flow into the penis, which guarantees a stable erection. But despite the fact that the increase in blood flow after taking the drug lasts 4-5 hours, the erection stops immediately after the end of the sexual act and sexual stimulation is required again to resume it. This is how the remedy works on a man, but many are wondering what will happen if a girl drinks Viagra?

The biology of men and women is fundamentally different, so Viagra cannot have the same effect on the beautiful half of humanity as it does on men. But to say that the tool does not affect their body at all is also impossible. The increase in blood flow in the pelvic organs of women after the use of the drug will occur in full, and this may even increase the feeling of excitement, if it is already present, but only in this case. Since, unlike men, the sexual arousal of women depends more on psychological reasons than on physiological characteristics, Viagra cannot eliminate the cause of a decrease in sexual desire in women.
In other words, if a woman who is sexually attracted to a man and wants to have sex with him drinks a Viagra pill, then most likely she will get new interesting sensations that make sexual intercourse more vivid.

But if there is no sexual desire at all for some reason, then Viagra will not be able to provoke it, let alone lead to orgasm. Therefore, taking the drug is not recommended for patients suffering from a decrease in libido, lack of sexual desire.

The only thing that Viagra can help women with is the lack of production of secretions that make the process of penetration easier and more enjoyable. Due to the fact that the blood flow to the pelvic organs increases, the body begins to secrete much more lubrication. However, whether it is worth taking a serious drug that can affect the heart for this, instead of using the usual lubricants, is a big question.

Despite the widespread use of Viagra, the drug should not be started on its own, without prior consultation with a specialist, since there is a risk of occurrence and development of some serious side effects that can have a significant negative impact on the body. When prescribing the remedy, be sure to follow the dosage prescribed by your doctor.

Viagra drug price

The unique pharmaceutical properties of Viagra have led to the fact that the price of the drug has become extremely high when compared with other drugs. But, despite this, you can buy it in almost all pharmacies in the world. The final cost depends mainly on the concentration of the active substance in one tablet. In addition, the size of the package also matters. It is more profitable to buy Viagra in large packs of 12 pieces, then the cost of one tablet will decrease. As a rule, no more than one tablet is consumed per day, so it can be argued that a large package will last about two weeks or longer if taken on an occasional basis.

Another way to save on erectile dysfunction treatment is to replace Viagra with a cheaper generic. But even in this case, the price will not be affordable for everyone. And the quality of such substitutes is not always able to compare with the original drug. You can buy original Viagra in most countries only by prescription.

Viagra analogues

Generic Viagra, as a rule, are cheaper than the original, and this factor is decisive when choosing them. The most famous analogues of the drug:

• Cialis is a substitute based on the substance tadalafil. Its main difference from Viagra is that Cialis acts on the male body within 36 hours after taking the drug, so it should be taken according to a certain schedule and not less than an hour after eating. The same fact must be taken into account. If, in addition to Cialis, other drugs are taken that interact poorly with Cialis. The effect of Cialis on the body is expressed in the elimination of existing obstacles to blood circulation in the penis.
• Levitra is a potency regulator based on vardenafil. This drug has a similar effect to Viagra, since it also initiates the process of PDE-5 inhibition. At the same time, for an effective effect on the body, it is enough to take only 20 mg of the active substance, so that a significant effect appears after 15 minutes. Levitra has serious side effects. The study revealed that the use of the drug can lead to vision loss and optic neuropathy. If this happens, the drug should be stopped immediately and professional medical help should be sought.
• Impaza is a Russian drug based on antibodies to endothelial NO synthase. Indications for its use, insufficiency of the genital reaction, are a decrease or complete absence of sexual desire, as well as male menopause. By increasing the activity of endothelial NO-synthase, the patient's libido level, sexual satisfaction, and testosterone levels increase slightly. The drug contains lactose, which makes it unsuitable for a large group of people suffering from galactosemia, glucose malabsorption syndrome or lactase deficiency.
• Eromax is a unique preparation produced on the basis of natural ingredients. In its composition, you can find L-arginine, drone brood, bee pollen, ginseng roots, as well as some vitamins and minerals. At the same time, in fact, it is not a drug, but acts as an effective dietary supplement, therefore, among other things, it strengthens the immune system, has an antioxidant and anabolic effect on the body. the effect of one tablet lasts up to 8 hours, but the frequency of administration, in comparison with other analogues, increases to 3 tablets per day.
• Vuka vuka is another dietary supplement made from the roots of securinega virosa, heteromorph arborescens, caries edible, and a few other natural substances. The drug is successfully used in the complex treatment of chronic prostatitis. It is a source of flavanoids and tannins, which can stimulate an erection and restore male sexual health.

In addition, Viagra substitutes are presented on the pharmaceutical market, containing at their core the same active ingredient as the original drug - sildenafil. Among them are eroton, ergos, potential, viasan-lf, kamagra, potentsagra, revatio, dynamico, vizarsin, maxigra.

The drug Viagra is used to correct the sexual functions of men. The remedy is used for various psychogenic or physiological sexual disorders. If you want to try using Viagra in the treatment, the indications are clearly indicated in the instructions for use. Pills are prescribed if a man is concerned about:

• premature ejaculation,
• lack of potency
• poor erection of the penis.

The drug is available in tablet form (20 mg, 50 mg, 100 mg).

Drug properties

The drug Viagra stimulates the filling of the cavernous bodies of the penis with blood. As a result, the erection becomes long, and the sexual intercourse is long. Nitric oxide is released in the tissues of the penis. There is a relaxation of the smooth muscles of the penis, blood flow to the cavernous bodies increases. After taking Viagra, a long erection occurs, sexual desire increases. The drug provides a vivid and rich impression of sex, a long and powerful orgasm.

The tool helps to cope with various problems in the intimate sphere. Tablets help to restore male sexual functions, prevent premature ejaculation, improve sperm quality.

The drug helps to increase the natural production of testosterone. Viagra stabilizes the hormonal balance in the male body, helps to synthesize the necessary substances for sexual intercourse. The remedy is prescribed for erectile dysfunction, weak potency, premature ejaculation, psychogenic sexual disorders.

Taking Viagra, every man can feel like a real tiger in bed with a woman. It gives self-confidence, eliminates the fear of failure, increases sexual desire before sexual intercourse.

The drug is not effective if there is no sexual stimulation. The tool is intended for sexual intercourse and the treatment of erectile dysfunction. Before using this medication, you should consult your doctor. You should not take Viagra if there are contraindications to use.

On the drug reviews of men can be found, mostly positive. A large number of representatives of the stronger sex note that after taking this drug, there is a significant increase in potency. The penis quickly comes into an erect state in the process of intimacy. His erection lasts for a long time and allows you to have sexual intercourse in such a way as to fully satisfy your sexual partner.

The tool causes adverse reactions in isolated cases. In general, the drug is well tolerated by the body.

For a quick and reliable improvement in potency, our readers advise M16 spray. This is a natural remedy that comprehensively affects the causes of erectile dysfunction. The composition of "M16" includes only natural ingredients with maximum efficiency. Due to its composition, the drug is absolutely safe, has no contraindications and side effects.

Composition of Viagra

The drug contains sildenafil citrate. 1 tablet contains 25 mg of sildenafil. This substance provides a stable erection, due to the improvement of blood circulation in the genitals. The substance has a beneficial effect on sexual functions, provides excellent potency and long sexual intercourse. Sildenafil quickly dilates blood vessels, relieves spasms, blocks the production of enzymes that constrict blood vessels in the male genital organs.

As additional substances Viagra includes microcrystalline cellulose, calcium, magnesium, sodium.

There is also a separate- read his instructions and reviews.

Viagra: indications for use

The main indications for taking this drug:

• impaired erection of the penis;
• sexual disorders of unknown etiology;
• maintaining an erection of the penis during intercourse;
• providing a bright and long orgasm;
• stabilization of testosterone production;
• erectile disfunction;
• adjustment of male sexual functions.

The drug is intended to improve the sexual performance of men. It is prescribed to eliminate sexual disorders, restore potency and erection. The drug is indicated for reduced desire for sex, short intercourse, soft orgasm.

Contraindications for admission

There are contraindications to the use of Viagra. The drug should not be taken if present:

• heart disease;
• kidney failure;
• bleeding;
• anemia;
• thrombosis;
• leukemia;
• heart rhythm disturbances;
• hypotension;
• arterial hypertension;
• hypertension;
• angina.

It is better to refrain from taking the medication after a stroke and myocardial infarction. The drug has a strong effect on the work of the heart, so you should be careful to take pills to all cores.

Viagra is not prescribed in childhood and adolescence. Also, the medicine is contraindicated in women. For women, there are other drugs that mimic the exciting effect of Viagra.

Tablets are incompatible for use in conjunction with medicines that enhance the effects of sildenafil. Viagra increases the hypotensive effect of nitrates. It is unacceptable to use the drug with individual intolerance.

When planning to take the drug, consider contraindications. With the development of various undesirable effects, you should stop the pills and be sure to consult a medical specialist. Perhaps the doctor will change the remedy.

Instructions for use and optimal dosages

The tablet is taken orally, ie. inside the body. It is necessary to swallow the whole capsule and drink it with water. The recommended dose is 50 mg. The tablet must be taken 1 hour before the intended sexual intercourse. In some cases, the dosage is increased to 100 mg or, conversely, reduced to 25 mg. The dose of the tablet is calculated individually, depending on the present violations of sexual function.

The maximum allowed to use no more than 100 mg per day. It is recommended to take the drug once a day.

Elderly men do not require a special correction of the dosage of the drug. The drug is indicated for admission from 18 years to old age.

Compatibility with other drugs

Side effects of the pathogen

This drug can cause unwanted reactions from the body. Often there is a headache and a flush of heat. With an increase in the dose of the drug, the development of side effects is observed. Often develop:

• allergy;
• blurred vision;
• discomfort in the eyeballs;
• increased intraocular pressure;
• vascular disease;
• hearing loss;
• leukopenia;
• anemia;
• respiratory disorders;
• heartbeat;
• dyspepsia;
• nausea;
• digestive disorders;
• ejaculation disorder.

If any adverse reaction occurs on the part of the male body, it is required to stop using the medication.

Viagra analogs

Similar potency stimulants have similar pharmacological effects. Means of this group are used to correct sexual dysfunction in men. The drugs have a beneficial effect on the potency and erection of the penis. Viagra appeared on the domestic market in 1998. Since then, many similar products have been developed. The most famous analogues of Viagra:

What is better Cialis or Viagra

Cialis can be an effective replacement for Viagra. The tool increases potency and allows you to have sexual intercourse without any problems. The drug provides a stable erection of the penis, filling the penis with blood. Cialis can be taken by men aged 18-70. The active drug substance of this drug is tadalafil. The component provides a rush of blood to the penis and has a positive effect on the sexual functions of men.

The average price of Cialis is 2289 rubles.

Comparison with Levitra

Levitra is a well-known analogue of Viagra, which can be used for erectile dysfunction. The drug has the same pharmacological effect as Viagra. Levitra - a means to improve potency. It provides a stable long erection of the penis, improved sexual life, getting a brighter and longer orgasm. The active ingredient in Levitra is vardenafil.

The average price of Levitra is 1487 rubles per package.

Impaza or Viagra

Impaza is a good alternative to Viagra in the event that taking this medication is not possible for any reason. Impaza provides a long-lasting erection to the penis, fills the male genital organ with blood. Taking the remedy helps prevent premature ejaculation and impotence.

The average cost of Impaza is 460 rubles.

Eroton is a drug that is designed to eliminate erectile dysfunction in men. The drug is well tolerated by the body and rarely causes side effects. The drug provides good potency, enhances sexual desire, promotes the natural production of male hormones. Eroton - pills that will help prolong sexual intercourse, relieve fatigue and fear of intimacy.

Potential - an analogue of Viagra, used for poor potency. The effect of the drug remains for a long time. It is important to take into account the features of the remedy - the drug can cause headache and dizziness. In general, all pills to improve potency have a powerful vasodilating effect. They should be used with caution with a tendency to high blood pressure, after a stroke and heart attack.

The average price of Potencil is 335 rubles.

Price and terms of use of the drug

As for Viagra itself, this drug begins to act immediately after absorption in the body. The effect of Viagra is felt within 20 minutes after taking and lasts more than 4 hours. It is recommended to take Viagra immediately before sexual intimacy. The drug is quite effective. It, like analogues, provides a long-lasting erection of the penis. It should be noted that such a kind of remedy as Royal Viagra provides a therapeutic effect for about 7 days. The drug has a prolonged action and gives a powerful positive result.

The price of Viagra is about 620 rubles (25 mg) - 685 rubles (50 mg). The cost of tablets of the drug 100 mg - 811 rubles.

The drug should be stored at room temperature in a dark place. It is undesirable to use these tablets without prior consultation with a doctor. The remedy must be taken to eliminate the present sexual disorders under the supervision of a physician. Medical correction provides complete relief from erectile dysfunction. Treatment of sexual dysfunction should be under medical supervision. It is impossible to self-medicate, this is fraught with deterioration in health and the wrong choice of therapeutic agents.