Children 1 year of age and older weighing 45 kilograms kg or more—20 mg 3 times a day. If you buy sildenafil for erectile dysfunction, it can also be known by the brand names Viagra, Aronix, Liberize and Nipatra. The studies that established benefit demonstrated improvements in success rates for sexual intercourse compared with placebo. VIAGRA was evaluated primarily at doses of 25 mg, 50 mg and mg in 21 randomized, double-blind, placebo-controlled trials of up to 6 months in duration, using a variety of study designs fixed dose, titration, parallel, crossover. In this case, just leave out the missed dose and take your next dose at the usual time. Viagra had no effect on saquinavir pharmacokinetics.Viagra is available in three strengths: 25 milligrams (mg), 50 mg, and mg. What are the typical dosages of Viagra? Typically, your doctor will start you on the recommended . Viagra; Descriptions. Sildenafil is used to treat men who have erectile dysfunction (also called sexual impotence). Sildenafil belongs to a group of medicines called . Sildenafil (Viagra) is used to treat erectile dysfunction (impotence; inability to get or keep an erection) in men. Sildenafil (Liqrev, Revatio) is used to improve the ability to exercise in adults (Liqrev, Revatio) and children 1 year of age and older (Revatio) with pulmonary arterial hypertension (PAH; high blood pressure in the vessels carrying blood to the .