Active substances: sildenafil (as citrate) 50 mg, excipients: microcrystalline cellulose 54 mg, lactose monohydrate 74 mg, croscarmellose sodium 10 mg, povidone 10 mg, magnesium stearate 2 mg. The composition of the film shell: Opadry II (polyvinyl alcohol, partially hydrolyzed 2.4 mg, titanium dioxide 1.374 mg, macrogol 1.212 mg, talc 0.888 mg, aluminum lacquer based on brilliant blue 0.1152 mg, ferric oxide (II) yellow 0.0102 mg, ferric oxide (II ) black 0.0006 mg).
Drug for the treatment of erectile dysfunction. Sildenafil citrate is a potent and selective inhibitor of cGMP-specific phosphodiesterase type 5 (PDE5). The physiological mechanism of penile erection involves the release of nitric oxide (NO) in the cavernous body during sexual stimulation. Nitric oxide activates the enzyme guanylate cyclase, which leads to an increase in the level of cyclic guanosine monophosphate (cGMP), relaxation of the smooth muscles of the cavernous body and increased blood flow in the penis. Sildenafil does not have a direct relaxing effect on an isolated cavernous body, but actively enhances the relaxing effect of NO on this tissue by inhibiting PDE5, which is responsible for the breakdown of cGMP in the cavernous body. When sexually aroused, the local release of NO under the influence of sildenafil leads to inhibition of PDE5 and an increase in cGMP level in the cavernous body, resulting in relaxation of smooth muscles and increased blood flow in the cavernous body. The use of sildenafil in the recommended doses is ineffective in the absence of sexual stimulation.
Erectile dysfunction, characterized by the inability to achieve or maintain an erection of the penis, sufficient for satisfactory sexual intercourse. The drug Viagra is effective only in the presence of sexual stimulation.
- hypersensitivity to the drug. The drug is contraindicated for use in patients who receive continuously or intermittently donators of nitric oxide, organic nitrates or nitrates in any form, since sildenafil enhances the hypotensive effect of nitrates, taken continuously or in emergency cases.
Use during pregnancy and lactation
On the part of the body as a whole: asthenia, pain, abdominal pain, back pain, infection, flu-like syndrome. Since the cardiovascular system: vasodilation (a side effect reported in clinical studies). On the part of the digestive system: diarrhea, nausea. From the musculoskeletal system: pain in the joints, muscle pain. On the part of the central nervous system and peripheral nervous system: dizziness (a side effect recorded in clinical studies), increased muscle tone, insomnia. On the part of the respiratory system: nasal congestion, pharyngitis, rhinitis (a side effect recorded in clinical studies), sinusitis, respiratory tract infections, impaired respiratory function. Dermatological reactions: rash. On the part of the sense organs: a change in vision: a slight and transient, mainly a change in the color of objects, as well as enhanced perception of light and blurred vision (a side effect recorded in clinical studies), conjunctivitis. On the part of the urinary system: urinary tract infections. On the part of the reproductive system: dysfunction of the prostate gland. When using the drug in doses exceeding the recommended, side effects were similar to those noted above, but were usually more common. The following are unwanted effects from the post-marketing application process. Since the cardiovascular system: arterial hypotension, syncope, tachycardia, palpitations. On the part of the digestive system: vomiting (a side effect reported in clinical studies). On the part of the reproductive system: prolonged erection and / or priapism. From the senses: pain in the eyes, redness of the eyes. Other: allergic reactions. Side effects were usually transient and mild or moderately severe. In studies with fixed doses, the incidence of side effects increased with increasing doses. The nature of side effects in studies in which the dose was selected, since such studies better reflect the recommended regimen of use, was comparable to that in studies with fixed doses.
Dosage and administration
The drug is taken orally. For most patients, the recommended dose is 50 mg; the drug is taken, if necessary, about 1 hour before sexual activity.Given the efficacy and tolerability, the dose may be increased to 100 mg or reduced to 25 mg. The maximum recommended frequency of use is 1 time / day. When using the drug in patients over the age of 65 years, patients with impaired liver function, patients with severe renal failure, as well as in patients receiving concomitant drugs - CYP3A4 isoenzyme inhibitors of the cytochrome P450 system (for example, erythromycin, saquinavir), there is an increase in sildenafil in plasma, which may contribute to an increase in the effectiveness of the drug, and the possibility of side effects. Even more potent CYP3A4 isoenzyme inhibitors of the cytochrome P450 system, such as ketoconazole or itraconazole, can be expected to increase plasma levels of sildenafil. It is necessary to discuss the feasibility of prescribing the drug in a dose of 25 mg / day in such groups of patients. The drug is not intended for use in patients under the age of 18 years.
A single dose of antacids (magnesium hydroxide / aluminum hydroxide) simultaneously with sildenafil does not affect its bioavailability. Enhances the hypotensive effect of nitrates (concomitant use is contraindicated) and the antiaggregatory effect of sodium nitroprusside. When taken simultaneously with acetylsalicylic acid (150 mg) does not increase the bleeding time. Inhibitors of CYP3A4 (cimetidine, ketoconazole, itraconazole, erythromycin, etc.) increase the concentration of sildenafil in plasma (in particular, cimetidine at a dose of 800 mg - by 56%, when taking sildenafil at a dose of 50 mg) and reduce its excretion. With a single dose of 100 mg of sildenafil on the background of the equilibrium concentration of erythromycin (taking 500 mg twice a day for 5 days) AUC of sildenafil increases by 182%, against the background of the equilibrium concentration of saquinavir (1200 mg 3 times a day) Cmax of sildenafil increases by 140% , AUC - by 210%. A single dose of 100 mg of sildenafil on the background of the equilibrium concentration of ritonavir, a powerful inhibitor of cytochrome P450 (400 mg 2 times a day), leads to a 4-fold (by 300%) increase in Cmax and an 11-fold (by 1000%) increase in AUC of sildenafil. Sildenafil has no effect on the pharmacokinetics of ritonavir and saquinavir. CYP2C9 invertors (tolbutamid), warfarin, CYP2D6 effects on the pharmacokinetics of sildenafil.It is assumed that while taking sildenafil with inducers of CYP3A4 (rifampicin, etc.), its plasma concentration will decrease. AUC of the active metabolite of sildenafil is increased by 62% when taking loop and potassium-sparing diuretics and 102% when taking non-specific beta-blockers (the clinical significance of these effects has not been determined). There were no signs of interaction with amlodipine (5 and 10 mg): the average additional lowering of blood pressure in the supine position (SBP at 8 mm Hg, DAD at 7 mm Hg) is comparable to that in healthy volunteers taking sildenafil alone. Does not enhance the hypotensive effect of alcohol in healthy volunteers at blood alcohol concentrations up to 80 mg / dl.
Interaction with other drugs