VIA GRA (VIAGRA) INSTRUCTIONS FOR USE

Trade name of the drug: Viagra

International non-proprietary 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 aluminum varnish based on indigo carmine (E132)) and opadry transparent YS-2-19114-A (contains hypromellose and triacetin )
Up to 30 µg/g of vanillin and/or biotin can be added to the blue film coating, with the content of one or both components in the film coating being 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, diamond-shaped, slightly biconvex, with cut and rounded edges, debossed with Pfizer on one side and VGR 25 , VGR 50 or VGR 100 on the other side, respectively.

Pharmacotherapeutic group: PDE5 inhibitor for the treatment of erectile dysfunction

ATX code: G04BE03

Pharmacological properties

Pharmacodynamics

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

Mechanism of action

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 nitric oxide (NO) through the 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 4,000 times more selective for PDE5 than PDE3, which is of paramount 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.

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 mm Hg. Art., and diastolic pressure of 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 (CHD) (more than 70% of patients had stenosis of at least one coronary artery), resting systolic and diastolic pressure decreased by 7 % and 6%, respectively, and pulmonary systolic pressure decreased by 9%. Sildenafil did not affect cardiac output and did not impair blood flow in stenotic coronary arteries, and also led to an increase (by approximately 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 angina symptoms improved. 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 antihypertensive drugs. 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 than three 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 slight 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 changes in vision assessed by special 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 trials lasting up to 6 months in 3000 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, 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 to 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, 59% of patients with diabetes, 43% of patients undergoing radical prostatectomy and 83% of patients with spinal cord injuries (vs. ).