Which drug class has the following effects: lowers blood pressure, reduces conductivity and contractility of the heart, dilates the arteries, reduces oxygen demand, and can cause bradycardia and peripheral edema?

• A. ACE Inhibitors
• B. Beta Blockers
• C. Diuretics
• D. Calcium Channel Blockers

Answer: (D)

Calcium channel blockers block calcium entry into vascular smooth muscle and cardiac muscle, producing a set of linked effects. By relaxing arterial smooth muscle, they dilate arteries and lower blood pressure. In the heart, reduced calcium entry slows conduction through the AV node and decreases contractility, which lowers myocardial oxygen demand as the heart beats more slowly and with less force. The combination of vasodilation, negative inotropy, and negative chronotropy explains why bradycardia can occur and why peripheral edema is a possible side effect—the arterial dilation can raise capillary hydrostatic pressure in the extremities, promoting fluid leakage into tissues. While other classes also lower BP, they don’t simultaneously produce the same extent of conduction slowing and negative inotropy with the same pattern of arterial dilation and edema, making calcium channel blockers the best fit for all the listed effects.