Which medication is known for relaxing the muscles of the heart and blood vessels?

Verapamil is known for its ability to relax the muscles of the heart and blood vessels, making it an effective medication for treating conditions such as hypertension and certain types of arrhythmias. It is classified as a calcium channel blocker, which means it inhibits the entry of calcium into heart and vascular smooth muscle cells. This leads to vasodilation (widening of blood vessels) and decreases the heart's workload by reducing the strength and rate of contractions. Consequently, this helps to lower blood pressure and improve blood flow.

In contrast, while amlodipine is also a calcium channel blocker, its specific effect is primarily on vascular smooth muscle rather than cardiac muscle directly. Furosemide is a loop diuretic that works by promoting the excretion of sodium and water, primarily affecting fluid balance rather than muscle relaxation. Propranolol is a beta-blocker that decreases heart rate and myocardial oxygen demand but does not specifically cause relaxation of blood vessels in the same manner as verapamil. Therefore, verapamil is the medication that plays a key role in relaxing both heart and vascular muscle.