Viagra, pills 50mg, 12pcs

Composition

Active ingredient:

sildenafil (in citrate form) 50 mg.

Auxiliary substances:

microcrystalline cellulose,

calcium hydrophosphate,

croscarmellose sodium,

magnesium stearate.

Composition of the film shell:

Opadry blue OY-LS-20921 (hypromellose, lactose, triacetin, titanium dioxide (E171), indigo carmine-based aluminum varnish (E132)) and Opadry transparent YS-2-19114-A (hypromellose, triacetin).

Pharmacological action

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

The realization 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 cGMP levels, subsequent relaxation of the smooth muscle tissue of the cavernous body, and increased blood flow.

Sildenafil does not have a direct relaxing effect on the isolated cavernous body in humans, but enhances the effect of 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 of other known phosphodiesterase isoenzymes: PDE6-by 10 times; PDE1-by more than 80 times; PDE2, PDE4, PDE7-PDE11 – by more than 700 times. Sildenafil is 4000 times more selective for PDE5 compared to PDE3, which is of crucial 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.

Indications

Treatment of erectile dysfunction characterized by the inability to achieve or maintain a penile erection sufficient for satisfactory sexual intercourse.

Sildenafil is effective only in the presence of sexual stimulation.

Contraindications

• Hypersensitivity to sildenafil or to any component of the drug;
• application in patients receiving constantly or intermittently donators of nitric oxide, organic nitrates or nitrates in any form, as sildenafil enhances the hypotensive effect of nitrates;
• it is not recommended to use the drug in conjunction with other means for the treatment of erectile dysfunction (safety and efficacy of combination therapy has not been studied);
• the drug is not intended for use in children and adolescents under the age of 18;
• the drug is not intended for use in women.

With caution: with anatomical deformity of the penis, with angulation, cavernous fibrosis, Peyronie’s disease, with diseases predisposing to the development of priapism, sickle cell anemia, multiple myeloma, leukemia, thrombocytopenia, with diseases accompanied by bleeding, with exacerbation of gastric and duodenal ulcers, with hereditary retinitis pigmentosa, with heart failure, with unstable angina pectoris, with previous 6 months of myocardial infarction, stroke, severe, life-threatening arrhythmias, hypertension (blood pressure more than 170/100 mm Hg), hypotension (blood pressure less than 90/50 mm Hg).

Side effects

Side effects are usually transient and mild to moderate.

The frequency of adverse events increases with increasing dose.

Nervous system: dizziness-sildenafil (% ) – 2.9, placebo (% ) – 1.0. Most often (>1/10) – headache-sildenafil (% ) – 10.8, placebo (% ) – 2.8. >

Cardiovascular system: increased heart rate-sildenafil (% ) – 1.0, placebo (% ) – 0.2. Often (>1/100 and >< 1/10) – vasodilation (flushing of blood to the face) – sildenafil (% ) – 10.9, placebo (% ) – 1.4.

Organ of vision: changes in vision (blurred vision, changes in sensitivity to light) – sildenafil (% ) – 2.5, placebo (% ) – 0.4. Chromatopsy (mild and transient, mainly changes in the perception of color shades) – sildenafil (% ) – 1.1, placebo (% ) – 0.03.

Respiratory system: rhinitis (nasal congestion) – sildenafil (% ) – 2.1, placebo (% ) – 0.3.

Digestive system: dyspepsia-sildenafil (% ) – 3.0, placebo (% ) – 0.4.

When using the drug in doses higher than recommended, side effects were similar to those noted above, but usually occurred more frequently.

Allergic reactions: hypersensitivity reactions (including skin rash).

From the central nervous system: convulsions.

From the cardiovascular system: tachycardia, decreased blood pressure, syncope, nosebleeds.

From the digestive system: vomiting.

From the side of the organ of vision: pain in the eyes, redness of the eyes/injections of the sclera.

On the part of the reproductive system: prolonged erection and / or priapism.

Interaction

Effect of other drugs on the metabolism of sildenafil

Metabolism of sildenafil occurs mainly in the liver under the action of isoenzymes CYP3A4 (main pathway) and CYP2C9, so inhibitors of these isoenzymes can reduce the clearance of sildenafil, and inducers, respectively, increase the clearance of sildenafil.

Concomitant use of CYP3A4 inhibitors (such as ketoconazole, erythromycin, cimetidine ) there was a decrease in the clearance of sildenafil.

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

A single dose of 100 mg of sildenafil concomitantly with erythromycin, a specific CYP3A4 inhibitor (when taking erythromycin 2 times / day for 500 mg for 5 days), while achieving a constant level of erythromycin in the blood leads to an increase in the AUC of sildenafil by 182%.

With simultaneous use of sildenafil (a single dose of 100 mg) and saquinavir, which is both an HIV protease inhibitor and a CYP3A4 inhibitor (when saquinavir is taken 3 times a day at a dose of 1200 mg), against the background of achieving a constant level of saquinavir in the blood, the cmax of sildenafil in the blood increased by 140%, and the AUC increased by 210%. Sildenafil had no effect on the pharmacokinetic parameters of saquinavir.

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

Simultaneous use of sildenafil (a single dose of 100 mg) and ritonavir, which is an HIV protease inhibitor and a strong inhibitor of cytochrome P450 isoenzymes (when taking ritonavir 500 mg 2 times / day), against the background of achieving a constant level of ritonavir in the blood, cmax of sildenafil increased by 300% (4 times), and AUC by 1000% (11 times). After 24 hours, the concentration of sildenafil in the blood plasma was approximately 200 ng / ml (with a single application of sildenafil alone-5 ng/ml).

If sildenafil is taken at the recommended doses in patients receiving strong CYP3A4 inhibitors at the same time, the cmax of free sildenafil does not exceed 200 nM, and the drug is well tolerated.

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

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

Concomitant use of azithromycin (500 mg / day for 3 days) does not affect the AUC, cmax, tmax, elimination rate constant, and T 1/2 of sildenafil or its main circulating metabolite.

Effect of sildenafil on other medications

Sildenafil is a weak inhibitor of cytochrome P450 isoenzymes-1A2,2C9,2C19,2D6,2E1, and 3A4 (IR 50 >150 mmol). It is unlikely that sildenafil can affect the clearance of substrates of these isoenzymes.

Sildenafil enhances the hypotensive effect of nitrates both with prolonged use and when used for acute indications. In this regard, the use of sildenafil in combination with nitrates or nitric oxide donors is contraindicated.

When the alpha-blocker doxazosin (4 mg and 8 mg) and sildenafil (25 mg,50 mg and 100 mg) were co – administered 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 mm Hg,9/5 mm Hg and 8/4 mm Hg, respectively, and in the standing position-6/6 mm Hg,11/4 mm hg and 4/5 mmHg, respectively. Rare cases of symptomatic postural hypotension, which manifested as dizziness (without fainting), have been reported in such patients. In some sensitive patients receiving alpha-blockers, concomitant use of sildenafil may lead to symptomatic hypotension.

No significant interaction of sildenafil with tolbutamide (250 mg) or warfarin (40 mg), which are metabolized by CYP2C9, was detected.

Sildenafil at a dose of 100 mg does not affect the pharmacokinetic parameters of HIV protease inhibitors at a constant concentration in the blood, such as saquinavir and ritonavir, which are both substrates of CYP3A4.

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 ethanol in healthy volunteers with a maximum blood ethanol level of an average of 80 mg/dl.

In patients with arterial hypertension, there were no signs of interaction between sildenafil (100 mg) and amlodipine. The average additional decrease in blood pressure in the supine position is: systolic – by 8 mm Hg, diastolic-by 7 mm Hg.

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

How to take, course of use and dosage

The drug is taken orally.

For most patients, the recommended dose is 50 mg approximately 1 hour before sexual activity. Depending on the efficacy 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 application is 1 time/day.

With mild to moderate renal failure

In patients with mild to moderate renal insufficiency ( creatinine clearance 30-80 ml/min), no dose adjustment is required.

In severe renal insufficiency (CC

With impaired liver function

In case of impaired liver function, the dose of the drug can be reduced to 25 mg.

When combined with ritonavir

When combined with ritonavir, the maximum single dose of Viagra should be 25 mg, the frequency of use – 1 time in 48 hours.

When combined with inhibitors of the CYP3A4 isoenzyme

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

In patients taking alpha-blockers

To minimize the risk of postural hypotension in patients taking alpha-blockers, sildenafil should be started only after hemodynamic stabilization has been achieved in these patients. Consideration should be given to reducing the initial dose of Viagra.

Overdose

Symptoms: with a single dose of the drug up to 800 mg, adverse events were comparable to those with sildenafil in lower doses, but were more common.

Treatment: if necessary, conduct symptomatic therapy. Hemodialysis does not accelerate the clearance of sildenafil, since the latter is actively bound to plasma proteins and is not excreted in the urine.

Special instructions

To diagnose erectile dysfunction, determine their possible causes, and choose appropriate treatment, it is necessary to collect a complete medical history and conduct a thorough physical examination.

Sexual activity poses a certain risk in heart diseases; therefore, before starting any therapy for erectile dysfunction, the doctor may consider it necessary to examine the cardiovascular system. Sexual activity is undesirable in patients with heart failure, unstable angina, a history of myocardial infarction or stroke in the last 6 months, life-threatening arrhythmias, arterial hypertension (BP>170/100 mm Hg) or hypotension (BP>

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

Viagra has a systemic vasodilating effect, which leads to a transient decrease in blood pressure. This effect is not clinically significant and does not lead to any consequences in most patients. However, before prescribing Viagra, the doctor should carefully weigh the risk of undesirable manifestations of vasodilating effects in patients with certain comorbidities, especially against the background of sexual activity. Increased susceptibility to vasodilators is observed in patients with obstruction of the left ventricular exit tract (for example, aortic stenosis, hypertrophic obstructive cardiomyopathy), as well as with the rare multiple systemic atrophy syndrome, manifested by a severe violation of blood pressure regulation by the autonomic nervous system.

Influence on the ability to drive motor vehicles and manage mechanisms

While taking the drug Viagra, no negative effect on the ability to drive a car or other technical means was observed. However, since taking the drug may reduce blood pressure, develop chromatopsia, blurred vision, 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.

Form of production

Tablets

Storage conditions

In a dry place, at a temperature not exceeding 30 °C

Shelf life

5 years

Active ingredient

Sildenafil

Conditions of release from pharmacies

By prescription

Dosage form

Tablets

Purpose

For men, For adults as prescribed by a doctor

Indications

Erectile Dysfunction