Diltiazem

Diltiazem is a calcium channel blocker and belongs to the benzothiazepine class of derivatives. It blocks L-type calcium channels, inhibiting calcium entry into cardiac muscle cells and vascular smooth muscle cells, and reducing calcium influx during the plateau phase of the action potential. In the heart, it suppresses depolarization of the sinoatrial node, lowers heart rate, inhibits atrioventricular nodal conduction, prolongs conduction time, and reduces myocardial contractility. In blood vessels, it relaxes coronary arteries and peripheral vascular smooth muscle, causing vasodilation, lowering peripheral resistance, and potentially decreasing blood pressure, thereby reducing cardiac afterload.