SILDENAFIL is an oral therapy for erectile dysfunction of a broad range of causes. By selectively inhibiting phosphodiesterase type 5, it allows corpus cavernosum smooth muscle to relax, potentiating erections during sexual stimulation. Blood pressure is reduced transiently by sildenafil, but more marked hypotension may occur during concurrent administration of sildenafil and organic nitrates; this combination is contraindicated. Sildenafil is rapidly absorbed, with dose-proportional peak plasma concentrations within 1 hour of administration. The elimination half-life is 3 to 5 hours. Dosages usually begin at 50mg taken when needed =1 hour before sexual activity no more than once daily. The maximum dose is 100mg when needed once daily and lower doses (e.g. 25mg) may be used in elderly patients and those with hepatic or renal impairment or receiving cytochrome P450 enzyme CYP3A4 inhibitors, such as ritonavir, saquinavir, ketoconazole, erythromycin or cimetidine. More than 3000 patients with erectile dysfunction of organic (e.g. diabetes or spinal cord injury), psychogenic or mixed origin received sildenafil 5 to 100mg or placebo in fixed- or titrated-dose trials. Sildenafil was associated with dose-related improvements in the frequency, hardness and duration of erections and in patients’ abilities to achieve and maintain erections adequate for successful sexual intercourse. In titrated-dose trials, the most commonly effective doses were 50 or 100mg, although lower doses were effective in some patients. Sildenafil was significantly more effective than placebo in erectile dysfunction of all tested causes.
VIAGRA (sildenafil citrate), an oral therapy for erectile dysfunction, is the citrate salt of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase type 5 (PDE5).
Sildenafil citrate is designated chemically as 1-[[3-(6,7-dihydro-1-methyl-7-oxo-3-propyl-1H-pyrazolo[4,3d]pyrimidin-5-yl)-4-ethoxyphenyl sulfonyl-4-methylpiperazine citrate and has the following structural formula.
Sildenafil citrate is a white to off-white crystalline powder with a solubility of 3.5 mg/mL in water and a molecular weight of 666.7. Sildenafil, sold as the brand name Viagra among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. It is unclear if it is effective for treating sexual dysfunction in women. It is taken by mouth or injection into a vein
Changes in functional scores from baseline were not statistically significant with the 100-mg dose compared with the 50-mg dose in the DBPC. Measures of treatment satisfaction and sexual experience significantly favored the 100-mg dose compared with the 50-mg dose in the DBPC. There was no increase in adverse events with the higher dose.
Sildenafil comes in three forms: an oral tablet, an oral suspension (liquid), and an injection that’s only given by a doctor. 100% active.