What is the role of calcium-channel blockers in the management of hypertension?

Calcium-channel blockers play a significant role in the management of hypertension primarily by relaxing vascular smooth muscle. This relaxation leads to vasodilation, which subsequently decreases systemic vascular resistance. Additionally, while calcium-channel blockers can have an effect on cardiac output, their primary mechanism in the context of hypertension is through reducing vascular resistance rather than directly decreasing the output of the heart itself.

When the vascular smooth muscle relaxes, the blood vessels widen, allowing blood to flow more easily. This reduces the pressure within the vessels, leading to lower blood pressure. Although some calcium-channel blockers can decrease heart rate and, in some cases, cardiac output as a secondary effect, their main therapeutic action remains focused on promoting vasodilation.

Other options do not accurately represent the mechanism by which calcium-channel blockers function. For instance, increasing systemic vascular resistance would be counterproductive to treating hypertension. Similarly, enhancing natriuresis and diuresis is more typically associated with diuretic medications. Blocking the action of angiotensin II pertains specifically to the class of medications known as angiotensin receptor blockers (ARBs) or angiotensin-converting enzyme (ACE) inhibitors, rather than calcium-channel blockers.