Overview & Mechanism of Action Nifedipine is an oral dihydropyridine calcium-channel blocker primarily used to treat hypertension, variant (Prinzmetal's) angina, and chronic stable angina. It works by inhibiting the influx of extracellular calcium through the membrane pores of myocardial and vascular smooth muscle cells, effectively plugging the channels. Unlike other calcium channel blockers (such as verapamil and diltiazem) that act evenly on the SA/AV nodes and vasculature, nifedipine acts predominantly as a potent peripheral vasodilator with negligible effects on AV nodal conduction. This vasodilation decreases total peripheral resistance, systemic blood pressure, and afterload. For variant angina, it increases myocardial oxygen supply by inducing coronary vasodilation; for chronic stable angina, it decreases myocardial o ...