What are examples of nitrates?

• A. Fenofibrate, gemfibrozil, bezafibrate.
• B. Glyceryl trinitrate (GTN), isosorbide dinitrate, isosorbide mononitrate.
• C. Atenolol, metoprolol, propranolol.
• D. Nifedipine, amlodipine, felodipine.

Answer: (B)

Nitrates are organic nitrate vasodilators that release nitric oxide, which relaxes vascular smooth muscle. The classic examples are glyceryl trinitrate (nitroglycerin), isosorbide dinitrate, and isosorbide mononitrate. These drugs are used in angina because they dilate veins more than arteries, lowering preload and reducing myocardial oxygen demand, with some improvement in coronary perfusion. Glyceryl trinitrate is commonly used for rapid, short-term relief (often sublingually), while isosorbide dinitrate and isosorbide mononitrate are longer-acting options. The other drug groups shown belong to different classes: fibrates for lipid lowering, beta-blockers that reduce heart rate and contractility, and calcium channel blockers that inhibit calcium entry but are not nitrates.