What Is Viagra?
Viagra is a brand name for sildenafil, an FDA-approved medication used to treat erectile dysfunction. It is a PDE5 inhibitor that helps increase blood flow during sexual stimulation. It does not cause erections on its own, and it is not safe for everyone — especially people who take nitrates.
Written by Virantus Editorial Team
Medically reviewed by Virantus Clinical Team · Reviewed August 2026
Last updated August 2026
Viagra and sildenafil
Viagra is the brand name; sildenafil is the active ingredient. Generic sildenafil may be prescribed when a clinician and pharmacy determine it is appropriate. Brand availability is not a medical claim about which product you will receive.
Sildenafil belongs to a class of drugs called PDE5 inhibitors. During sexual stimulation, it helps relax blood vessels in the penis, allowing increased blood flow. Arousal is still required — it is not an aphrodisiac.
How it is typically used
Most men take sildenafil about 30–60 minutes before sexual activity. Effects typically last about 4–6 hours, though individual response varies. A clinician determines the appropriate dose based on your health history, other medications, and cardiovascular status.
REQUIRES PROFESSIONAL REVIEW: Specific dosing protocols must be confirmed before launch.
Who may it be appropriate for?
Sildenafil may be appropriate for men with erectile dysfunction when a licensed clinician determines it is safe. It is not appropriate for everyone — particularly those taking nitrates for heart conditions, certain blood pressure medications, or with specific cardiovascular risks.
A private clinical evaluation helps determine whether sildenafil or another approach is right for you.
Common questions
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