Which adverse effect is commonly associated with non-dihydropyridine calcium channel blockers?

• A. Constipation
• B. Dizziness
• C. Headache
• D. Bradycardia

Answer: (D)

Non-dihydropyridine calcium channel blockers primarily affect the heart’s electrical system, slowing conduction through the SA and AV nodes. This negative chronotropic effect lowers the heart rate, so bradycardia is a common and clinically important adverse effect of these drugs. It’s especially important to monitor pulse and rhythm in patients who may already have conduction abnormalities or who are taking other rate-lowering medications, because significant bradycardia can reduce cardiac output and cause symptoms like dizziness or fainting.

Dizziness and headaches can occur with these drugs due to systemic vasodilation, and constipation is a known issue with verapamil, but the most characteristic and expected adverse effect to watch for with non-dihydropyridine calcium channel blockers is bradycardia.