Like other prescription medicines, Viagra and its generic form, sildenafil, work best when you take them under the right conditions. From your mental state to your eating habits, a range of factors ...

Viagra is a prescription tablet that’s used to treat erectile dysfunction in adults. It comes in three strengths (25 mg, 50 mg, and 100 mg) and is taken as needed up to 4 hours before sexual activity.

Sildenafil citrate, or simply sildenafil, is the active ingredient in the brand-name drug Viagra. Sildenafil is known as generic Viagra because retailers do not sell it under the Viagra brand name.

Viagra is available in 25-milligram (mg), 50-mg, and 100-mg doses, with the typical starting dose being 50 mg taken an hour before sexual activity. The maximum recommended dosage is 100 mg per day.