What is the primary hemodynamic effect of calcium channel blockers on blood pressure?

• A. Arterial Vasodilation Increasing Afterload
• B. Venous Dilation Reducing Preload
• C. Increased Heart Rate
• D. Arterial Vasodilation Reducing Afterload

Answer: (D)

Calcium channel blockers lower blood pressure primarily by relaxing arterial smooth muscle, which leads to arterial dilation. When the arteries dilate, systemic vascular resistance drops, so the left ventricle pumps against less resistance. That reduction in afterload is the main hemodynamic change that lowers blood pressure.

Some agents also affect heart rate or conduction, and venous effects are less prominent, but the key mechanism driving the BP effect is arterial vasodilation reducing afterload.