What is the mechanism of action of calcium channel blockers like amlodipine?

Calcium channel blockers, such as amlodipine, primarily work by inhibiting the influx of calcium ions through L-type calcium channels in both vascular smooth muscle and cardiac cells. This action leads to several physiological effects, including vasodilation and a reduction in myocardial contractility.

In vascular smooth muscle, the blockage of calcium entry causes relaxation, resulting in decreased vascular resistance and lowered blood pressure. In cardiac tissue, the reduced calcium influx leads to a decrease in the force of contraction and heart rate, contributing to the drug's overall antihypertensive and antianginal properties. Hence, the mechanism of action directly targets calcium channels, which is essential for muscle contraction and vascular tone.

Understanding the mechanism of action of calcium channel blockers is critical for appreciating their role in managing conditions like hypertension and angina.