Which medication is a calcium channel blocker used to treat hypertension?

• A. Metformin
• B. Levofloxacin
• C. Amlodipine
• D. Gabapentin

Answer: (C)

Calcium channel blockers lower blood pressure by blocking L-type calcium channels in vascular smooth muscle, which reduces calcium entry into the cells. With less calcium, the smooth muscle relaxes, the arterioles dilate, peripheral resistance falls, and blood pressure decreases. Amlodipine is a dihydropyridine calcium channel blocker commonly used for hypertension and angina because it produces effective arterial dilation with long-lasting effects suitable for once-daily dosing. Side effects often include peripheral edema from the dilation of small vessels. The other medications listed are not calcium channel blockers for hypertension: metformin treats diabetes, levofloxacin is an antibiotic, and gabapentin is used for seizures and neuropathic pain and is not a standard antihypertensive.