Which of the following is a common adverse effect of calcium channel blocker therapy?

• A. Headache
• B. Nausea
• C. Rash
• D. Dizziness

Answer: (A)

Calcium channel blockers cause vasodilation by blocking calcium entry into vascular smooth muscle, which lowers systemic vascular resistance. This dilation extends to cerebral vessels, and the resulting cerebral vasodilation commonly presents as a headache, especially when therapy starts. While some patients may also feel dizziness from lower blood pressure or, less often, experience nausea or a rash, headache is the most typical adverse effect associated with these medications. If headaches are bothersome, assess blood pressure, ensure safety with activities, and consider symptomatic relief per clinician guidance, while monitoring for signs of excessive hypotension.