Viagra tablet color. How to take Viagra for the first time? Which is better Cialis or Viagra

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

Description

The film-coated tablets are blue, biconvex, rounded diamond-shaped, marked “Pfizer” on one side and “VGR 50” (for a 50 mg dosage) or “VGR 100” (for a 100 mg dosage) on the other side.

Pharmacotherapeutic group

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

ATX code G04BE03

Pharmacological properties

Pharmacokinetics

Suction

After oral administration, sildenafil is rapidly absorbed. Maximum plasma concentrations (Cmax) of sildenafil are achieved within a period of 30 to 120 minutes (median 60 minutes) after oral administration on an empty stomach. The average absolute bioavailability after oral administration of the drug 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 values increase in direct proportion to the dose taken.

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

Distribution

The average steady-state volume of distribution (Vd) for sildenafil is 105 L, indicating its distribution in body tissues.

After oral administration of sildenafil in a single dose of 100 mg, the average 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 blood plasma is 18 ng/ml (38 nM). Protein binding is independent of total drug concentrations.

In healthy volunteers who received a single dose of sildenafil 100 mg, less than 0.0002% (on average 188 ng) of the dose taken was detected in the ejaculate 90 minutes after taking the dose.

Metabolism

In vitro studies

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

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

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 (IC50 > 150 μM). Given that maximum plasma concentrations of sildenafil after taking recommended doses of the drug are approximately 1 μM, it is unlikely that sildenafil will alter the clearance of substrates of these isoenzymes.

Removal

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

Pharmacokinetics in special groups of patients

Elderly patients

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

In patients with mild or moderate renal impairment (creatinine clearance 30-80 ml/min), the pharmacokinetics of sildenafil after a single oral dose of 50 mg does not change. The increase in mean 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 renal impairment. However, due to the high variability between patients, these differences were not statistically significant. In patients with severe renal impairment (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), the clearance of sildenafil 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 liver dysfunction 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 corpora cavernosa upon sexual stimulation. Nitric oxide activates the enzyme guanylate cyclase, which leads to increased levels of cyclic guanosine monophosphate (cGMP), subsequent relaxation of smooth muscle in the cavernous bodies and increased blood flow.

Sildenafil is a strong and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5), 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, PDE5 inhibition by sildenafil results in increased cGMP levels in the corpora cavernosa. Therefore, for sildenafil to provide the desired productive pharmacological effect, sexual stimulation is necessary.

Pharmacodynamic effects

In vitro studies

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

Clinical efficacy and safety

The safety and effectiveness of sildenafil have been confirmed by long-term studies.

Indications for use

Erectile dysfunction, characterized by the inability to achieve or maintain a penile erection sufficient for satisfactory sexual intercourse.

Viagra® is effective only with sexual stimulation.

Directions for use and doses

For oral use.

Viagra® can be taken with or without food. However, Viagra® may take longer to take effect when taken with food.

Dosage regimen

Use in adults

The recommended dose of Viagra® is 50 mg orally approximately 1 hour before sexual intercourse. Taking into account effectiveness and tolerability, the dose can be increased to 100 mg. The maximum recommended dose is 100 mg.

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

Special patient groups

Elderly patients

In elderly patients (≥ 65 years), no dose adjustment is required.

Patients with impaired renal function

For mild to moderate renal impairment (creatinine clearance 30-80 ml/min), no dose adjustment is required. Due to decreased 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 liver dysfunction

Due to the fact that the clearance of sildenafil is reduced in patients with impaired liver function (for example, cirrhosis), the use of 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 to 50 mg and 100 mg.

Patients of childhood and adolescence

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

Use in patients taking other medications

In order to reduce the risk of postural hypotension in patients treated with alpha-blockers, the condition of patients receiving alpha-blockers should be stabilized before starting treatment with sildenafil. In addition, the use of 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 occurrence 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 vision distortions (chloropsia, chromatopsia, cyanopsia, erythropsia, xanthopsia), visual disturbances, blurred vision

Hyperemia, hot flashes

Nasal congestion

Dyspepsia, nausea

Hypersensitivity

Drowsiness, hypoesthesia

Disorders associated with lacrimation (dry eyes, dysfunction of the lacrimal gland, increased lacrimation), eye pain, photophobia, photopsia, hyperemia of the blood vessels of the eyes, brightness of visual perception, conjunctivitis

Spatial disorientation (vertigo), tinnitus

Tachycardia, palpitations

Arterial hypertension, arterial hypotension

Nosebleeds, sinus congestion

Upper abdominal pain, gastroesophageal reflux disease, vomiting, dry mouth

Myalgia, pain in limbs

Hematuria

Chest pain, fatigue, feeling hot

Increased heart rate

Acute cerebrovascular accident, transient ischemic attack, seizure*, relapse of seizure*, syncope

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, vitreous floaters, iris disease, mydriasis, the presence of iridescent circles in the field of view, oedema of the eye, swelling of the eye, visual disturbances, 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, dry nasal mucosa

Oral hypoesthesia

Stevens-Johnson syndrome*, toxic epidermal necrolysis*

Bleeding from the penis, priapism*, hematospermia, increased erection
- irritability

*side effects recorded only during post-marketing surveillance.

Reporting Suspected Adverse Reactions

Reporting suspected adverse reactions detected after drug registration is of great importance. This allows continued monitoring of the benefit-risk ratio of the drug.

Healthcare professionals and patients are asked to report any adverse reactions to the address listed at the end of this prescribing information.

Contraindications

Hypersensitivity to the active substance or to any of the excipients

Simultaneous use of drugs that donate nitric oxide (amyl nitrite) or nitrates in any form

Concomitant use with guanylate cyclase stimulators (riociguat)

Severe liver failure

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

Loss of vision in one eye due to anterior nonarteritic ischemic optic neuropathy, whether or not related to prior use of a PDE5 inhibitor

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

Severe cardiovascular disease (eg, severe heart failure, unstable angina)

Myocardial infarction in the last 6 months

Stroke in the last 6 months

Concomitant use with inhibitors of the CYP3A4 isoenzyme (for example, 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 galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption syndrome

Concomitant use with other oral or local drugs for the treatment of erectile dysfunction

Carefully:

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

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

§ problems with blood clotting (hemophilia)

§ diseases accompanied by bleeding

§ exacerbation of gastric or duodenal ulcers

§ simultaneous use with drugs of the alpha-blocker group

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

Drug interactions

Effect of other drugs on sildenafil

In vivo studies

When sildenafil is taken concomitantly with CYP3A4 inhibitors (such as ketoconazole, erythromycin and cimetidine), a decrease in the clearance of sildenafil is observed. This group of patients does not experience an increased incidence of side effects; however, it is necessary to begin treatment with Viagra® at an initial dose of 25 mg.

Co-administration of the HIV protease inhibitor ritonavir, which is a strong cytochrome P450 inhibitor, at steady state (500 mg twice daily) 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 the AUC of sildenafil in blood plasma by 1000% (11-fold). After 24 hours, sildenafil plasma levels 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 a wide range of cytochrome P450 substrates. Based on the above data, the simultaneous use of sildenafil with ritonavir is not recommended.

Viagra® does not affect the pharmacokinetics of ritonavir.

The maximum dose of sildenafil should under no circumstances exceed 25 mg in 48 hours.

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

When a single 100 mg dose of sildenafil was taken with erythromycin, a moderate CYP3A4 inhibitor, at steady state (500 mg twice daily for 5 days), there was a 182% increase in systemic exposure to sildenafil (as determined by AUC value).

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.

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

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

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, calcium channel blockers, beta-adrenergic blockers receptors and inducers of P450 metabolic activity (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) results in a decrease in AUC and Cmax values for sildenafil by 62.6% and 55.4%, respectively. Thus, it is believed that concomitant use with strong CYP3A4 inducers, such as rifampin, causes a more pronounced decrease in sildenafil plasma concentrations.

Concomitant use with other PDE5 inhibitors or other treatments for erectile dysfunction

The safety and effectiveness of sildenafil in combination with other PDE5 inhibitors or other sildenafil-containing drugs for the treatment of pulmonary arterial hypertension (PAH) or other drugs for the treatment of erectile dysfunction. In this regard, the use of such combinations of drugs is not recommended.

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

Effect of sildenafil on other drugs

In vitro studies

There are no data on the interaction of sildenafil with nonspecific phosphodiesterase inhibitors such as theophylline or dipyridamole.

In vivo studies

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

Riociguat

In clinical studies, riociguat enhanced the hypotensive effect of PDE5 inhibitors. There were no data on a beneficial clinical effect with this combination in the studied population. Concomitant use of riociguat with PDE5 inhibitors, including sildenafil, is contraindicated.

Concomitant use with alpha-blockers

It is recommended to use sildenafil with caution in patients taking alpha-blockers, since their simultaneous use may lead to symptomatic arterial hypotension in some sensitive patients. This is most likely to occur within 4 hours of taking a dose of sildenafil. To reduce the risk of developing postural hypotension, a state of hemodynamic stability should be achieved in patients receiving treatment with alpha-blockers before starting treatment with sildenafil. The use of 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.

Rare cases of symptomatic hypotension, dizziness, and lightheadedness, but not syncope, have been reported during concomitant use of sildenafil and doxazosin in patients stabilized on doxazosin therapy.

When sildenafil (50 mg dose) was co-administered with tolbutamide (250 mg dose) or warfarin (40 mg dose), 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 enhance the hypotensive effects of alcohol in healthy volunteers with an average maximum blood alcohol level of 80 mg/dl.

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

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

When coadministered with bosentan, sildenafil at steady state (80 mg three times daily) increased the AUC and Cmax of bosentan (125 mg twice daily) by 49.8% and 42%, respectively, in healthy male volunteers.

special instructions

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

Risk factors for cardiovascular disease

Before initiating treatment for erectile dysfunction, healthcare providers should evaluate the cardiovascular status of their patients, as there is a certain degree of risk for cardiac complications associated with sexual activity.

Before prescribing sildenafil, physicians should carefully evaluate the potential for adverse effects of the drug's vasodilatory effects on patients with certain underlying medical conditions, especially when combined with sexual activity. The group of hypersensitivity to vasodilators includes patients with narrowing of the left ventricular outflow tract (for example, aortic valve stenosis, hypertrophic obstructive cardiomyopathy), as well as patients with the rare syndrome of multiple system atrophy, which manifests itself in the form of severe impairment of autonomic blood pressure control.

Sildenafil leads to a slight and short-term decrease in blood pressure, which in most cases has no clinical manifestations. The mean maximum reduction in supine systolic blood pressure following oral sildenafil 100 mg was 8.4 mmHg. 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 an increase in cGMP levels in vascular smooth muscle. A single oral dose of sildenafil up to 100 mg in healthy volunteers did not cause any clinically significant changes in the ECG.

In patients with severe coronary heart disease (CHD), 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 nitric oxide/cyclic guanosine monophosphate (cGMP) metabolic pathway, sildenafil is capable of enhancing the hypotensive effect of nitrates, therefore its simultaneous use with nitric oxide donors (such as amyl nitrite) or nitrates is contraindicated in any form.

During the post-marketing period, cases of serious cardiovascular complications, including myocardial infarction, unstable angina, sudden cardiac death, ventricular arrhythmia, cerebrovascular hemorrhage, transient ischemic attack, hypertension and hypotension, have been reported during the use of sildenafil. Most, but not all, of these patients had preexisting cardiovascular risk factors. Many of these events were reported during or shortly after completion of sexual intercourse, and several events were reported shortly after taking sildenafil without sexual activity. It is not possible to determine whether these events were related directly to sildenafil use, 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 anatomical deformation of the penis (such as angulation, cavernous fibrosis, or Peyronie's disease), as well as in patients with diseases that predispose to the development of priapism (such as crescentic -cellular anemia, multiple myeloma or leukemia).

During post-marketing use of sildenafil, cases of prolonged erection and priapism have been reported. In case of an erection lasting more than 4 hours, the patient should seek urgent medical attention. If not treated immediately, priapism can lead to damage to penile tissue and irreversible loss of potency.

Effect on vision

There have been cases of visual impairment in connection with taking sildenafil and other PDE5 inhibitors, namely a rare disease - anterior non-arteritic ischemic optic neuropathy. If any defects in visual acuity occur, you should 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 is no data on the safety of sildenafil in patients with bleeding disorders or active peptic ulcers, so sildenafil should be used after a careful benefit/risk assessment.

Viagra® should not be used in men with rare hereditary galactose intolerance, 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 in women.

There have been no adequate and strictly controlled studies of the use of Viagra® in pregnant and breastfeeding women.

Reproductive function

There was no effect of the drug on sperm motility or morphology after a single oral dose of sildenafil 100 mg.

Features of the effect of the drug on the ability to drive a 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 operating machinery, patients should find out how their body reacts to taking Viagra®, due to side effects of the drug, such as dizziness and visual disturbances.

Overdose

Adverse reactions reported in studies with a single dose of up to 800 mg of the drug in volunteers were comparable to those observed when using lower doses of the drug, but their incidence and severity were higher. Taking increased 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 of adverse reactions (headache, flushing, dizziness, dyspepsia, nasal congestion and visual disturbances).

Shelf life

Do not use after the expiration date.

Conditions for dispensing from pharmacies

On prescription

Manufacturer

Fareva Amboise,

Zone Industriale -29 route des Industries

37530 Potz-sur-Cisse, France

P N015875/01 dated 08/12/2009
Trade name of the drug: Viagra®
International nonproprietary name: sildenafil
Dosage form: film-coated tablets

Compound

1 film-coated tablet contains:
Active substance:
sildenafil citrate (equivalent to 25 mg, 50 mg or 100 mg sildenafil)
Excipients:
microcrystalline cellulose, calcium hydrogen phosphate, croscarmellose sodium, magnesium stearate; film shell: opadry blue OY-LS-20921 (contains hypromellose, lactose, triacetin, titanium dioxide (E171) and indigo carmine-based aluminum varnish (E132)) and opadry transparent YS-2-19114-A (contains hypromellose and triacetin)

Up to 30 µg/g vanillin and/or biotin can be added to the blue film coating; in this case, the content of one or both components in the film coating will be up to 0.75 μg, 1.5 μg and 3.0 μg for dosages of 25 mg, 50 mg and 100 mg, respectively.

Description

Blue, film-coated tablets are diamond-shaped, slightly biconvex, with beveled and rounded edges, debossed with "Pfizer" on one side and "VGR 25", "VGR 50" or "VGR 100" on the other side, respectively.

Pharmacotherapeutic group:

erectile dysfunction treatment – PDE5 inhibitor

ATX code: G04BE03

Pharmacological properties

Pharmacodynamics

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

Mechanism of action

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

Sildenafil does not have a direct relaxant effect on the isolated human corpus cavernosum, but enhances the effect of nitric oxide (NO) by inhibiting PDE5, which is responsible for the breakdown of cGMP.

Sildenafil is selective for PDE5 in vitro, its activity against PDE5 exceeds that 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 PDE3, which is of utmost importance since PDE3 is one of the key enzymes in the regulation of myocardial contractility.

A prerequisite for the effectiveness of sildenafil is sexual stimulation.

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 pressure in the supine position after taking sildenafil at a dose of 100 mg was 8.3 mmHg. Art., and diastolic pressure – 5.3 mm Hg. Art. A more pronounced, but also transient effect on blood pressure (BP) was observed in patients taking nitrates (see sections “Contraindications” and “Interaction with other drugs”).

In a study of the hemodynamic effect of sildenafil at a single dose of 100 mg in 14 patients with severe coronary artery disease (CAD) (more than 70% of patients had stenosis of at least one coronary artery), resting systolic and diastolic blood pressure decreased by 7 % and 6%, respectively, and pulmonary systolic pressure decreased by 9%. Sildenafil did not affect cardiac output or impair blood flow in stenotic coronary arteries, and also resulted in an increase (by approximately 13%) in 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 taking antianginal drugs (except nitrates) exercised until their angina symptoms improved. The duration of the exercise was significantly longer (19.9 seconds; 0.9 - 38.9 seconds) in patients taking sildenafil in a single dose of 100 mg compared to patients receiving placebo.

A randomized, double-blind, placebo-controlled study examined the effect of varying the dose of sildenafil (up to 100 mg) in men (n = 568) with erectile dysfunction and hypertension taking more than two antihypertensive medications. Sildenafil improved erections in 71% of men compared to 18% in the placebo group. The incidence of adverse effects was comparable to that in other patient groups, as well as in individuals taking more than three antihypertensive drugs.

Visual impairment studies
In some patients, 1 hour after taking sildenafil at a dose of 100 mg, the Farnsworth-Munsell 100 test revealed a mild and transient impairment in the ability to distinguish shades of color (blue/green). 2 hours after taking the drug, these changes were absent. Color vision impairment is thought to be caused by inhibition of PDE6, which is involved in 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-onset macular degeneration (n = 9), sildenafil in a single dose of 100 mg was well tolerated. There were no clinically significant changes in vision assessed by specific visual tests (visual acuity, Amsler grating, color perception, color transmission simulation, Humphrey perimeter, and photostress).

Efficiency
The efficacy and safety of sildenafil was assessed in 21 randomized, double-blind, placebo-controlled studies lasting up to 6 months in 3,000 patients aged 19 to 87 with erectile dysfunction of various etiologies (organic, psychogenic or mixed). The effectiveness of the drug was assessed globally using an erection diary, the International Index of Erectile Function (a validated questionnaire about the state of sexual function) and a partner interview. The effectiveness of sildenafil, defined as the ability to achieve and maintain an erection sufficient for satisfactory sexual intercourse, has been demonstrated in all studies conducted and was confirmed in long-term studies lasting 1 year. In fixed-dose studies, the proportion of patients who reported that 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. Analysis of the International Index of Erectile Function showed that in addition to improving erection, treatment with sildenafil also increased the quality of orgasm, achieved satisfaction from sexual intercourse and overall satisfaction.

According to the pooled data, among patients who reported improved erections with sildenafil treatment, 59% of patients with diabetes, 43% of patients who had undergone radical prostatectomy and 83% of patients with spinal cord injury (versus 16%, 15% and 12% in the placebo group, respectively) ).

Pharmacokinetics

Suction

After oral administration, sildenafil is rapidly absorbed. Absolute bioavailability averages about 40% (from 25% to 63%). In vitro sildenafil at a concentration of about 1.7 ng/ml (3.5 nM) inhibits human PDE5 activity by 50%. After a single dose of sildenafil 100 mg, the average maximum plasma concentration of free sildenafil (Cmax) in men is about 18 ng/ml (38 nM). Cmax when taking sildenafil orally on an empty stomach is achieved on average within 60 minutes (from 30 minutes to 120 minutes). When taken in combination with fatty foods, the rate of absorption decreases: Cmax decreases by an average of 29%, and the time to reach maximum concentration (Tmax) increases by 60 minutes, but the degree of absorption does not significantly change (the area under the concentration-time pharmacokinetic curve (AUC) decreases by 11%).

Distribution

The volume of distribution of sildenafil at steady 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 the drug. Less than 0.0002% of the sildenafil dose (average 188 ng) was found in semen 90 minutes after dosing.

Metabolism
Sildenafil is metabolized mainly in the liver under the influence of the cytochrome isoenzyme CYP3A4 (major pathway) and the cytochrome isoenzyme CYP2C9 (minor pathway). The main circulating active metabolite resulting from N-demethylation of sildenafil undergoes further metabolism. The selectivity of this metabolite for PDE is comparable to that of sildenafil, and its activity for PDE5 in vitro is about 50% of the activity of sildenafil. The concentration of the metabolite in the blood plasma of healthy volunteers was about 40% of the concentration of sildenafil. The N-demethyl metabolite undergoes further metabolism; its half-life (T1/2) is about 4 hours.

Removal

The total clearance of sildenafil is 41 l/hour, and the final T1/2 is 3-5 hours. After oral administration, as after intravenous administration, sildenafil is excreted in the form of metabolites, mainly by the intestines (about 80% of the oral dose) and, to a lesser extent, by the kidneys (about 13% of the oral dose).

Pharmacokinetics in special groups of patients

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

Renal dysfunction
With mild (creatinine clearance (CL) 50-80 ml/min) and moderate (CL 30-49 ml/min) degrees of renal failure, the pharmacokinetics of sildenafil after a single oral dose of 50 mg does not change. In severe renal failure (creatinine clearance (30 ml/min)), the clearance of sildenafil is reduced, which leads to an approximately twofold increase in AUC (100%) and Cmax (88%) compared to those with normal renal function in patients of the same age group.

Liver dysfunction
In patients with liver cirrhosis (stages A and B according to the Child-Pugh classification), the clearance of sildenafil is reduced, which leads to an increase in AUC (84%) and Cmax (47%) compared with those with normal liver function in patients of the same age groups. The pharmacokinetics of sildenafil in patients with severe liver dysfunction (Child-Pugh stage C) has not been studied.

Indications for use

Treatment of erectile dysfunction, characterized by the inability to achieve or maintain a penile erection sufficient for satisfactory sexual intercourse. Sildenafil is only effective during sexual stimulation.

Contraindications

Hypersensitivity to sildenafil or any other component of the drug.
Use in patients receiving continuous or intermittent nitric oxide donors, organic nitrates or nitrites in any form, since sildenafil enhances the hypotensive effect of nitrates (see section “Interaction with other drugs”)
The safety and effectiveness of Viagra® when used in combination with other drugs for the treatment of erectile dysfunction have not been studied, therefore the use of such combinations is not recommended (see section "Special Instructions")
According to its registered indication, Viagra® is not intended for use in children under 18 years of age.
According to its registered indication, Viagra® is not intended for use in women

Carefully

Anatomical deformation of the penis (angulation, cavernous fibrosis or Peyronie's disease) (see section "Special instructions")
- Diseases predisposing to the development of priapism (sickle cell anemia, multiple myeloma, leukemia, thrombocythemia) (see section “Special instructions”)
- Diseases accompanied by bleeding
- Exacerbation of peptic ulcer disease
- Hereditary retinitis pigmentosa (see section “Special instructions”)
- Heart failure, unstable angina, myocardial infarction, stroke or life-threatening arrhythmias in the last 6 months, arterial hypertension (BP > 170/100 mm Hg) or hypotension (BP< 90/50 мм рт. ст.) (см. раздел «Особые указания»)

Pregnancy and lactation

According to the registered indication, the drug is not intended for use in women

Directions for use and doses
Inside.

The recommended dose for most adult patients is 50 mg approximately 1 hour before sexual activity. Taking into account effectiveness and tolerability, the dose can be increased to 100 mg or reduced to 25 mg. The maximum recommended dose is 100 mg. The maximum recommended frequency of use is once a day.

Renal dysfunction
For mild to moderate renal failure (CR 30-80 ml/min), no dose adjustment is required; for severe renal failure (CR< 30 мл/мин) – дозу силденафила следует снизить до 25 мг.

Liver dysfunction
Since the elimination of sildenafil is impaired in patients with liver damage (particularly with cirrhosis), the dose of Viagra® should be reduced to 25 mg.

Concomitant use with other drugs
When used together with ritonavir, the maximum single dose of Viagra® should not exceed 25 mg, and the frequency of use should not be 1 time per 48 hours (see section “Interaction with other drugs”).
When used together with inhibitors of the cytochrome CYP3A4 isoenzyme (erythromycin, saquinavir, ketoconazole, itraconazole), the initial dose of Viagra® should be 25 mg (see section “Interaction with other drugs”).
To minimize the risk of developing postural hypotension in patients taking β-blockers, Viagra should be started only after hemodynamic stabilization has been achieved in these patients. You should also consider the advisability of reducing the initial dose of sildenafil (see sections “Special instructions” and “Interaction with other drugs”).

Elderly patients
No dose adjustment of Viagra® is required.

Side effect

Typically, the side effects of Viagra® are mild or moderate and transient.
Fixed-dose studies have shown that the incidence of some adverse events increases with increasing dose.

Organs and organ systems	Side effects	Sildenafil,%	Placebo, %
Most common side effects (> 1/10)
Nervous system	Headache	10,8	2,8
The cardiovascular system	Vasodilation (“flushes”) to the skin of the face)	10,9	1,4
Frequent side effects (> 1/100 and< 1/10)
Nervous system	Dizziness	2,9	1,0
Organ of vision	Changes in vision (blurred vision, changes in sensitivity to the light)	2,5	0,4
	Chromatopsia (mild and transient, mainly changes in the perception of shades of color)	1,1	0,03
The cardiovascular system	Cardiopalmus	1,0	0,2
Respiratory system	Rhinitis (nasal congestion)	2,1	0,3
Digestive system	Dyspepsia	3,0	0,4

When using Viagra® in doses exceeding the recommended ones, adverse events were similar to those noted above, but usually occurred more often.
General condition disorders: hypersensitivity reactions (including skin rash).
Changes in the central and peripheral nervous system: convulsions.
Changes in the cardiovascular system: tachycardia, decreased blood pressure, fainting, nosebleeds.
Gastrointestinal disorders: vomit.
Changes in the organ of vision: eye pain, eye redness/scleral injection.

Reproductive system disorders: prolonged erection and/or priapism.

Overdose

With a single dose of Viagra® in a dose of up to 800 mg, adverse events were comparable to those when taking the drug in lower doses, but were more common. Treatment is symptomatic. Hemodialysis does not accelerate the clearance of sildenafil, since the latter actively binds to plasma proteins and is not excreted by the kidneys.

Interaction with other drugs
The influence of other drugs on the pharmacokinetics of sildenafil

The metabolism of sildenafil occurs mainly under the influence of the cytochrome isoenzymes CYP3A4 (the main pathway) and CYP2C9, therefore inhibitors of these isoenzymes can reduce the clearance of sildenafil, and inducers, accordingly, increase the clearance of sildenafil. A decrease in the clearance of sildenafil was noted with simultaneous use of inhibitors of the cytochrome CYP3A4 isoenzyme (ketoconazole, erythromycin, cimetidine). Cimetidine (800 mg), a nonspecific inhibitor of the cytochrome CYP3A4 isoenzyme, when taken together with sildenafil (50 mg), causes an increase in plasma sildenafil concentrations by 56%. A single dose of 100 mg of sildenafil together with erythromycin (500 mg/day 2 times a day for 5 days), a specific inhibitor of the cytochrome CYP3A4 isoenzyme, while achieving a constant concentration of erythromycin in the blood, leads to an increase in the AUC of sildenafil by 182%. When co-administered with sildenafil (100 mg once) and saquinavir (1200 mg/day 3 times a day), an inhibitor of HIV protease and the cytochrome CYP3A4 isoenzyme, while achieving a constant concentration of saquinavir in the blood, the Cmax of sildenafil increased by 140%, and the AUC increased by 210%. Sildenafil has no effect on the pharmacokinetics of saquinavir. Stronger inhibitors of the cytochrome CYP3A4 isoenzyme, such as ketoconazole and itraconazole, may cause more severe changes in the pharmacokinetics of sildenafil.
The simultaneous use of sildenafil (100 mg once) and ritonavir (500 mg 2 times a day), an HIV protease inhibitor and a strong cytochrome P450 inhibitor, while achieving a constant concentration of ritonavir in the blood leads to an increase in sildenafil Cmax by 300% (4 times ), and AUC by 1000% (11 times). After 24 hours, the concentration of sildenafil in the blood plasma is about 200 ng/ml (after a single use of sildenafil alone - 5 ng/ml).
If sildenafil is taken in recommended doses by patients simultaneously receiving strong inhibitors of the cytochrome CYP3A4 isoenzyme, then the Cmax of free sildenafil does not exceed 200 nM, and the drug is well tolerated.
A single dose of an antacid (magnesium hydroxide/aluminum hydroxide) does not affect the bioavailability of sildenafil.
Inhibitors of the cytochrome CYP2C9 isoenzyme (tolbutamide, warfarin), the cytochrome CYP2D6 isoenzyme (selective serotonin reuptake inhibitors, tricyclic antidepressants), thiazide and thiazide-like diuretics, ACE inhibitors and calcium antagonists do not affect the pharmacokinetics of sildenafil.
Azithromycin (500 mg/day for 3 days) has no effect on the AUC, Cmax, Tmax, elimination rate constant and T1/2 of sildenafil or its main circulating metabolite.

Effect of sildenafil on other drugs
Sildenafil is a weak inhibitor of cytochrome P450 isoenzymes - 1A2, 2C9, 2C19, 2D6, 2E1 and 3A4 (IC50>150 µmol). When sildenafil is taken at recommended doses, its Cmax is approximately 1 µmol, so it is unlikely that sildenafil could affect the clearance of substrates of these isoenzymes.

Sildenafil enhances the hypotensive effect of nitrates both with long-term use of the latter and when they are prescribed for acute indications. In this regard, the use of sildenafil in combination with nitrates or nitric oxide donors is contraindicated.
With simultaneous administration of the β-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 Art., 9/5 mm Hg. Art. and 8/4 mm Hg. Art., respectively, and in a standing position - 6/6 mm Hg. Art., 11/4 mm Hg. Art. and 4/5 mm Hg. Art., respectively. Rare cases of symptomatic postural hypotension, manifested in the form of dizziness (without fainting), have been reported in such patients. In some sensitive patients receiving beta-blockers, simultaneous use of sildenafil may lead to symptomatic hypotension.
There were no signs of significant interaction with tolbutamide (250 mg) or warfarin (40 mg), which are metabolized by the cytochrome CYP2C9 isoenzyme.
Sildenafil (100 mg) does not affect the pharmacokinetics of HIV protease inhibitors, saquinavir and ritonavir, which are substrates of the cytochrome CYP3A4 isoenzyme, at constant blood levels.
Sildenafil (50 mg) does not cause an additional increase in bleeding time when taking acetylsalicylic acid (150 mg).
Sildenafil (50 mg) does not enhance the hypotensive effect of alcohol in healthy volunteers with a maximum blood alcohol concentration of 0.08% (80 mg/dL) on average.
In patients with arterial hypertension, no signs of interaction between sildenafil (100 mg) and amlodipine were detected. The average additional decrease in blood pressure in the supine position is 8 mmHg. Art. (systolic) and 7 mm Hg. Art. (diastolic).
The use of sildenafil in combination with antihypertensive drugs does not lead to additional side effects.

special instructions

To diagnose erectile dysfunction, determine its possible causes and select adequate treatment, it is necessary to obtain a complete medical history and conduct a thorough physical examination.

Sexual activity poses a certain risk in the presence of heart disease, so before starting any therapy for erectile dysfunction, the doctor should refer the patient for an examination of the condition of the cardiovascular system. Sexual activity is not advisable in patients with heart failure, unstable angina, myocardial infarction or stroke in the last 6 months, life-threatening arrhythmias, arterial hypertension (BP > 170/100 mm Hg) or hypotension (BP< 90/50 мм рт. ст.) (см. раздел «С осторожностью»). 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.

Medicines intended to treat erectile dysfunction should not be prescribed to men for whom sexual activity is undesirable.

The drug Viagra® has a systemic vasodilating effect, leading to a transient decrease in blood pressure, which is not a clinically significant phenomenon and does not lead to any consequences in most patients. However, before prescribing Viagra®, the doctor must carefully assess the risk of possible undesirable 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 obstruction of the left ventricular outflow tract (aortic stenosis, hypertrophic obstructive cardiomyopathy), as well as with the rare syndrome of multiple system atrophy, manifested by severe dysregulation of blood pressure from the autonomic nervous system.

Rare cases of anterior ischemic optic neuropathy of non-arterial origin have been reported as a cause of deterioration or loss of vision with the use of all PDE5 inhibitors, including sildenafil. Most of these patients had risk factors such as excavation of the optic nerve head, age over 50 years, diabetes mellitus, hypertension, coronary artery disease (CHD), hyperlipidemia, and smoking. A cause-and-effect relationship between the use of PDE5 inhibitors and the development of anterior ischemic optic neuropathy of non-arterial origin has not been identified. The doctor should inform the patient about the increased risk of developing anterior ischemic optic neuropathy of non-arterial origin if he has previously had this condition. Since the combined use of sildenafil and β-blockers can lead to symptomatic hypotension in some sensitive patients, Viagra® should be prescribed with caution to patients taking β-blockers (see section “Interaction with other drugs”). To minimize the risk of developing postural hypotension in patients taking beta-blockers, Viagra® should be started only after hemodynamic stabilization has been achieved in these patients. You should also consider the advisability of reducing the initial dose of Viagra® (see section “Dosage and Administration”). The physician should inform patients about what actions to take if symptoms of postural hypotension occur.

A small number of patients with hereditary retinitis pigmentosa have genetically determined dysfunction 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 (see section “With caution”).

Sildenafil enhances the antiaggregation effect of sodium nitroprusside (nitric oxide donor) on human platelets in vitro. There is no information on the safety of using Viagra® in patients with internal bleeding or active peptic ulcers, so it should be used with caution (see section "With caution").

Erectile dysfunction treatments should be used with caution in patients with anatomical deformation of the penis (angulation, cavernous fibrosis, Peyronie's disease), or in patients with risk factors for priapism (sickle cell anemia, multiple myeloma, leukemia) (see section "Caution. ness").

The safety and effectiveness of Viagra® in combination with other drugs for the treatment of erectile dysfunction have not been studied, therefore the use of such combinations is not recommended (see section “Contraindications”).

In some post-marketing and clinical studies with all PDE5 inhibitors, including sildenafil, sudden decrease or loss of hearing in patients has been reported. However, most of these patients had risk factors for developing this pathology, and no correlation was found between the use of PDE5 inhibitors and sudden decrease or loss of hearing. If there is a sudden decrease or loss of hearing, you should stop taking sildenafil and consult your doctor immediately.

Impact on the ability to drive a car and use machinery

While taking sildenafil, no negative effects on the ability to drive a car or use other technical equipment were observed. However, since taking sildenafil may reduce blood pressure, develop chromatopsia, blurred vision, etc. side effects, you should carefully consider the individual effect of the drug in these situations, especially at the beginning of treatment and when changing the dosage regimen.

Release form

Film-coated tablets 25 mg, 50 mg or 100 mg

1, 2, 4, 8 or 12 tablets in a blister made of PVC/polyethylene/aclar/aluminum foil

1, 2 or 3 blisters in a cardboard box along with instructions for use

An additional protective logo is applied to the back of the blister (in Latin letters “Pfizer” in white on a dark blue background), changing color when the viewing angle changes. At the corners of the blister there are empty round contour cells for fixation in the production machine.

Perforated first opening control lines in the form of red semicircles are applied to the front side of the cardboard box on both right and left edges. A protective holographic sticker that changes color as the viewing angle changes is located in the lower right corner of the front surface of the pack.

The side surfaces of the pack are tightly glued together when packaging the drug.

Storage conditions

List B. Store in a dry place at a temperature not exceeding 30 .C
Keep out of the reach of children

Best before date

5 years
Do not use after the expiration date stated on the package

Conditions for dispensing from pharmacies
On prescription

Company manufacturer:

Pfizer PGM, France
Zone Industriel, 29 rue des Industri, 37530 Posay-sur-Sis, France
Direct consumer complaints
at the address of the company's representative office in the Russian Federation:
109147 Moscow, Taganskaya street, 21

Age-related changes occurring in a man’s body, injuries, bad habits, hereditary predisposition and other negative factors may not have the best effect on men’s health. The result of pathological changes is usually, which leads the representative of the stronger sex to experiences that gradually turn into.

With reduced erectile capabilities, the drug restores blood flow to the tissues of the penis during sexual arousal.

Viagra tablets

As a result of complex reactions, which are triggered by the drug entering the tissue, smooth muscles relax, which ensures unimpeded blood flow to the organ.

After completion of sexual intercourse, the process of blood flow in the tissues of the penis weakens, as a result of which an erection occurs naturally and occurs again only if the erogenous zones of the man are re-exposed.

Instructions for use of Viagra tablets for men

The drug is taken approximately 60 minutes before sexual intercourse. The recommended dose is 50 mg.

Depending on the individual characteristics of the man’s body, it is possible to increase the dose to 100 mg or reduce it to 25 mg. It is not recommended to exceed the dosage of 100 mg. Before you start taking the product, please contact.

The specialist will choose the dosage that is best suited for you. Viagra tablets are taken once a day. If you take the medicine on an empty stomach, the effect will be faster than when the tablets are taken after meals.

Elderly patients who have crossed the age threshold of 65 years do not require dosage adjustment. If the patient has mild or moderate renal impairment, dosages intended for middle-aged men are appropriate.

In case of severe disease, start taking the drug with 25 mg per day. If necessary and there are no side effects, the daily dosage is increased to 50 or 100 mg.

Why doesn't the drug help?

Viagra is not a miracle pill, but a medical drug whose action helps achieve an erection, but does not cause it immediately upon entering the body.

To achieve the desired effect, stimulation from the partner or is required.

In some cases, Viagra does not have the desired effect the first time it is used. In this case, it is necessary to try to use the product several more times and only in the absence of an erection, and in these cases, seek advice from a doctor.

The specialist will choose an analogue whose effect will be more acceptable for your body.

According to experts, the lack of a correct reaction to pills lies primarily in the genetic characteristics of a man’s body, which causes an individual, and sometimes even unpredictable, reaction of tissues and blood vessels to pills.

Also, a bad effect of the drug is often observed in overweight men who lose weight due to excess weight. In this case, additional is required.

Another reason that can explain the inaction of Viagra is the wrong choice of dosage. Some men need to take 100 mg of the drug to get an erection, rather than the 25 mg that doctors usually recommend to start with.

Is it possible to take Viagra for prostatitis?

If a man suffers, circulatory problems occur and...

Such conditions are ideal for the development of pathogens that provoke the development.

To prevent this from happening, a man needs to get rid of what has accumulated naturally (through ejaculation).

And since the release of semen without an erection is impossible, experts prescribe medications to patients that increase blood circulation in the organ. Viagra is also one of these drugs. Therefore, taking pills for prostatitis is allowed.

In order not to harm their health, patients suffering from prostatitis should always seek advice from a doctor before taking the drug. The specialist will choose the correct dosage and determine the appropriate intensity of administration.

Side effects and contraindications

In most cases, the drug is well tolerated by patients.

Sometimes, due to the individual characteristics of the body, the following side effects may occur:

insomnia;
tides;
headache;
in joints and muscle tissue;
nausea;
the appearance of a rash on the skin;
blurred vision;
respiratory tract diseases;
other unpleasant symptoms.

If one of the above conditions occurs, you should immediately stop taking Viagra and immediately seek help from a doctor.

The doctor will choose for you a synonym for the drug that does not cause such manifestations. Side effects can also cause conditions for which Viagra should not be used.

Contraindications for which the use of the drug is unacceptable include:

anatomical deformities of the penis;
individual intolerance to the ingredients included in the product;
exacerbation of stomach ulcers and other gastrointestinal diseases;
disorders of the liver and kidneys;
tendency to bleed;
severe form of hyper- or hypotension.

If you have the listed health problems, you should not take Viagra.

Analogs

There are a sufficient number of Viagra analogues on sale, produced by domestic and foreign manufacturers.

Synonyms include:

Adamax;
Vecta;
Viasil;
Jenagra;
Intagra;
many other drugs.

The choice of a Viagra substitute to avoid the development of complications should be made by the attending physician.

Price

The price of Viagra tablets may vary. This will depend on the dosage of the product, as well as on the seller’s pricing policy. On average, the cost of a drug can range from 649 to 1250 rubles. If you wish, you can save money by ordering the medicine from an online pharmacy.

is a drug for the treatment of erectile dysfunction and prolongation of sexual intercourse. The product is very popular among men of different ages and gives positive results after the first dose. Viagra enhances the effect of nitric oxide, as a result of which the muscles relax during natural stimulation and do not interfere with active blood circulation within the organs.

The active ingredient in Viagra is a selective inhibitor Sildenafil, which inhibits the PDE-5 enzyme, which constricts blood vessels and causes premature emission of seminal fluid. The component has a powerful effect on the body and has a number of contraindications. When taking Sildenafil, you should strictly follow the recommended dosage to avoid adverse reactions. Before using this product, you must undergo a basic examination and consultation with a doctor to exclude the presence of contraindications.

Photo Viagra 100 mg 10 tablets

Action time: up to 4 hours

Onset of action: after 30-50 minutes

Use with alcohol: incompatible

Viagra method of administration and dosage

It is recommended to use the product occasionally or as a course

Viagra should be taken an hour before sexual intercourse. The tablet should be taken with water or non-alcoholic liquid. The use of the drug does not depend on food intake. Viagra can be taken once every 24 hours, taking into account the individual characteristics of the body. The drug is recommended to be used occasionally for short-term enhancement of erection, and also taken during the full treatment course; in the second case, a better effect of the drug is observed:

after long-term use of Viagra, a man loses premature ejaculation
the condition of blood vessels significantly improves
erection becomes stronger and more stable
sexual intercourse lasts up to three times longer
testosterone levels increase

The maximum daily dose of Sildenafil is 100 milligrams. This amount of a potent substance is indicated only for young men. However, even for healthy patients, experts recommend starting with a lower dosage (no more than 50 milligrams). In most cases, this amount of Sildenafil is sufficient to obtain the expected result. In addition, it is recommended to reduce the daily dose if the drug is used regularly (more than twice a week), since the substance accumulates in the plasma in small quantities.

Viagra taken with alcohol

Viagra is not compatible with alcohol. When taking a medicine that contains the inhibitor Sildenafil, a man is contraindicated to drink alcohol in any doses and quantities. First of all, alcohol reduces the effectiveness of beneficial components. Once in the stomach, ethyl alcohol slows down the absorption of substances into the blood. As a result, they are absorbed slowly and incompletely. Their action begins later than the expected time and ends much faster. The therapeutic effectiveness of the product is reduced several times.

Alcohol increases the concentration of Sildenafil in plasma, which, in turn, can cause severe adverse reactions and serious complications of chronic diseases. Especially if it concerns pathologies of the liver or kidneys. When combining the drug with a small dose of alcohol, poisoning is possible, accompanied by negative consequences for the body. When using Viagra regularly for quality treatment of erectile dysfunction, it is necessary to avoid drinking alcohol of any percentage of strength. If the drug is taken occasionally, you should ensure that the time interval between taking alcoholic beverages and Viagra is at least 12 hours.

Drugs similar in effect to Viagra

Viagra taken with fatty foods

Products containing a high percentage of fat, like alcohol, reduce the effectiveness of medications and dietary supplements for the treatment of erectile dysfunction. Fats of plant or animal origin envelop the walls of the stomach from the inside and prevent the rapid absorption of active components.

If we consider this situation using the example of Sildenafil, then as a result of the action, Viagra is slowly absorbed. Her work starts much later and lasts less than four hours. Under the influence of fatty foods, the product does not give the expected result. The action of Viagra is negatively affected by foods whose fat content exceeds 30%; in order to get the maximum effect from treatment with Sildenafil, experts recommend excluding from the daily diet:

For high-quality absorption of the active substance, you should give preference to light foods, increase the amount of grains and fiber in the menu, consume more protein and complex carbohydrates, and maintain optimal water balance. Drink plenty of fluids. Focus on fresh fruits and vegetables. Along with adjusting the menu, pay attention to your physical condition. Do exercises in the morning, play sports and lead an active lifestyle. Remember that the cause of erectile dysfunction can be the abuse of bad habits. Stop smoking.

Drugs that prolong sex by 3 times

Viagra interaction with other drugs

Viagra is not compatible with medications that contain inhibitors. The combination of these medications with Sildenafil not only reduces the effectiveness of the inhibitor, but can also cause a deterioration in a person’s well-being. Viagra cannot be taken simultaneously with products that inhibit HIV: their ingredients increase the concentration of Sildenafil in the blood, which also entails the occurrence of adverse reactions.

Viagra is not recommended to be combined with drugs based on alpha blockers and nitrates. This drug should not be taken simultaneously with antidepressants and amphetamines. The drug is contraindicated in combination with other medications and biological supplements to restore erectile function. When taking vasodilator drugs, you should use the minimum dosage of Sildenafil (no more than 50 milligrams per day). Before using Viagra in combination with other medicinal substances that are not listed above, you must consult a qualified specialist and also read the instructions that are included in the package with the product.

What are the benefits of sex for a man, video

The video shows an experiment to understand the benefits of sex.