Viagra (Sildenafil): How It Works, What It Treats, When to Take It, and Available Alternatives
By John K. Matsuura, MD | Medically Reviewed by Christopher W. Boelter, MD | Last reviewed 2026-08-14 Viagra is the best-known brand name for sildenafil, a prescription medicine used to treat erectile dysfunction in adult men. Its arrival changed the way erectile dysfunction was discussed and managed: a problem that had often been treated with […]