Glossary term

Sildenafil

Also known as Viagra - Revatio

Short-acting PDE5 inhibitor and the generic form of Viagra. On-demand dosing, 4-6 hour clinical window.

Sildenafil is the original PDE5 inhibitor, with a plasma half-life of roughly 4 hours and a clinical window of 4-6 hours. Dosed 30-60 minutes before activity; a fatty meal delays onset. Response rates of 70-80% for organic ED at 50-100 mg. Absolute contraindications include nitrate use and recent major cardiac events. Drug interactions with alpha-blockers, CYP3A4 inhibitors, and riociguat require provider review before dispensing.

Medically reviewed byDr. Lena Okafor, MD

Medical Director - updated April 2026 - How we review