Sildenafil
C₂₂H₃₀N₆O₄S·474.576 g/mol·Pharmaceutical·CID 5212
DrugVasodilator
Viagra — a PDE5 inhibitor originally developed for angina. Increases cGMP levels, causing smooth muscle relaxation and vasodilation. Revolutionized treatment of erectile dysfunction. Also approved for pulmonary arterial hypertension (as Revatio).