Description of medicine: Sildenafil citrate (Sildenafil citrate)
SILDENAFIL CITRATE (Sildenafil citrate).
Citrate 1 - [[3- (6,7-Dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo [4,3-A] pyrimidin-5-yl) 4-ethoxyphenyl] sulfonyl] piperazine.
Synonym: Viagra, Viagra.
It was originally proposed as a cardiovascular agent, but was not effective enough; however, some male patients receiving it noted an increase in sexual potency; the drug was studied in this direction, the data were confirmed and sildenafil (called "Viagra") received medical use.
The mechanism of action is still not clear enough. From the point of view of biochemistry, the main importance is currently attached to the ability of sildenafil to selectively inhibit the activity of the type V phosphodiesterase enzyme, which inactivates cyclic guanosine monophosphate (c-GMF), which is involved in the relaxation of the smooth muscles of the cavernous body and improves blood supply to the penis. Sildenafil does not have a direct relaxing effect on the vessels of the cavernous body, but enhances the vasodilating effect of nitric oxide (NO) released during sexual stimulation in relation to this tissue. Obviously, stimulation of the spinal cord plays a physiological role, especially in the light of data on the effectiveness of the drug in potency disorders associated with spinal cord lesions.
When taken orally, it is rapidly and completely absorbed, bioavailability is 40%, Cmax - 60 minutes, T1 / 2 - 4 hours; undergoes intensive biotransformation in the liver with the formation of an active metabolite, excreted mainly with feces in the form of metabolites.
Assign inside (in the form of tablets), usually at a dose of 0.05 g (50 mg) 1 hour before sexual intercourse. Depending on the effect, the dose can be reduced to 0.025 g or increased to 0.1 g. The maximum recommended dose is 0.1 g 1 time per day.
According to reports, the drug is usually well tolerated. Possible side effects: headache, dizziness, dyspepsia, peripheral vasodilation (hot flashes), impaired light and color perception, clarity of vision, arthralgia and myalgia.
The drug is contraindicated in severe somatic diseases.
Cardiologists draw attention to the danger of using the drug by patients using nitrates (that is, a wide range of patients with coronary artery disease). In recent informational materials, the use of nitrates refers to contraindications for the appointment of Viagra. Endocrinologists recommend that patients with diabetes consult a cardiologist and an ophthalmologist. In general, it is advisable to use the drug on the advice of a doctor.
Release form: tablets on 0,025; 0.05 and 0.1 g (25; 50 and 100 mg) (N. 1, 4, 8, 12).