Both sildenafil and the metabolite have terminal half lives of about 4 hours. VIAGRA was administered to more than 3, patients aged 19 to 87 years, with ED of various etiologies organic, psychogenic, mixed with a mean duration of 5 years. Sexual function data were also recorded by patients in a daily diary. The primary endpoint was time to limiting angina in the evaluable cohort. The major circulating metabolite results from N-desmethylation of sildenafil, and is itself further metabolized. The possible categorical responses to these questions were 0 no attempted intercourse, 1 never or almost never, 2 a few times, 3 sometimes, 4 most times, and 5 almost always or always.Typical dosing for Sildenafil (Viagra) The typical dose is to take 50 mg of sildenafil (Viagra) by mouth, about 1 hour before sex, as needed. The maximum . The maximum dose of Viagra is mg each day. Doses above the maximum dose, such as mg per day, will increase the risk of side effects. And in . The Savings Offer and Program expire on 12/31/ For further information, call , visit test1.ru, or write: Viatris Inc., P.O. Box , Mission, KS .