What are the effects of calcium channel blockers?

Calcium channel blockers are a class of medications that primarily act on the heart and blood vessel smooth muscle to produce several therapeutic effects. The correct answer highlights that these medications decrease heart rate and lower blood pressure.

Calcium channel blockers work by inhibiting the influx of calcium ions through voltage-gated calcium channels in cardiac and smooth muscle cells. This action leads to several physiological effects:

1. Decrease Heart Rate: By blocking calcium channels in the cardiac cell membranes, these medications reduce the force of contraction of the heart muscles and slow down the conduction of electrical impulses through the sinoatrial (SA) and atrioventricular (AV) nodes. This results in a decreased heart rate, which is beneficial in conditions like hypertension or certain arrhythmias.

2. Lower Blood Pressure: The decrease in heart rate combined with the relaxation of vascular smooth muscle results in vasodilation. As the blood vessels relax and widen, the overall resistance against which the heart must pump (systemic vascular resistance) is reduced, leading to lower blood pressure. This makes calcium channel blockers useful in the management of hypertension and heart conditions involving tachycardia or angina.

Other options present different effects that do not align with the primary actions of calcium channel blockers