Amlodipine (Norvasc (Pfizer) and generics) (as besylate, mesylate or maleate) is a long-acting calcium channel blocker (dihydropyridine (DHP) class) used as an anti-hypertensive and in the treatment of angina. Like other calcium channel blockers, amlodipine acts by relaxing the smooth muscle in the arterial wall, decreasing total peripheral resistance and hence reducing blood pressure; in angina it increases blood flow to the heart muscle (although DHP-class calcium channel blockers are more selective for arteries than myocardium, as the cardiac calcium channels are not of the dihydropyridine-type).