Which of the following is an example of a calcium channel blocker used to treat Raynaud's phenomenon?

• A. Nifedipine
• B. Diltiazem
• C. Amlodipine
• D. Verapamil

Answer: (A)

Calcium channel blockers help Raynaud's by relaxing smooth muscle in peripheral arteries, promoting vasodilation and improved blood flow to the fingers and toes during vasospastic attacks. Nifedipine, a dihydropyridine calcium channel blocker, has the strongest evidence and is a classic first-line option for this condition because it produces potent peripheral vasodilation. While other choices listed are also calcium channel blockers, nifedipine is the best-known and most commonly used for Raynaud's due to its proven efficacy in reducing attack frequency and severity. Common side effects include headaches, flushing, edema, and possible hypotension.