Which of the following medications is classified as a calcium channel blocker?

• A. Spironolactone
• B. Furosemide
• C. Amlodipine
• D. Lansoprazole

Answer: (C)

Amlodipine is classified as a calcium channel blocker, which means it works by inhibiting the influx of calcium ions into vascular smooth muscle and cardiac muscle. This action leads to relaxation of the blood vessels (vasodilation), which decreases blood pressure and reduces the workload on the heart. It's commonly used in the management of hypertension and certain types of angina, making it an important medication in cardiovascular care.

In contrast, spironolactone is a potassium-sparing diuretic often used in conditions like heart failure and hypertension but does not fall under the calcium channel blocker category. Furosemide is a loop diuretic that helps in the management of edema associated with heart failure and is not related to calcium channel blocking mechanisms. Lansoprazole, on the other hand, is a proton pump inhibitor used primarily for gastrointestinal conditions such as acid reflux and ulcers, and it does not interact with calcium channels at all. Therefore, among the listed medications, amlodipine is the only one that directly acts as a calcium channel blocker.