In the same patient, which medication is a calcium channel blocker?

• A. Metformin
• B. Amlodipine
• C. Ramipril
• D. Furosemide

Answer: (B)

Calcium channel blockers work by preventing calcium ions from entering cells in the heart and blood vessels through L-type calcium channels, which lowers intracellular calcium and causes relaxation of vascular smooth muscle. This leads to vasodilation and reduced blood pressure.

Amlodipine is a dihydropyridine calcium channel blocker that mainly acts on arterial smooth muscle, producing vasodilation and a fall in blood pressure with relatively less effect on heart rate or conduction.

The other drugs belong to different classes: metformin is an oral antidiabetic agent, ramipril is an ACE inhibitor that reduces angiotensin II formation, and furosemide is a loop diuretic that increases urine output. None of these are calcium channel blockers.

So, the calcium channel blocker in this set is amlodipine.