Nitroglycerin, also known as glyceryl trinitrate, serves as a potent vasodilator primarily employed in medical settings to alleviate chest pain associated with angina pectoris stemming from coronary artery disease. By converting to nitric oxide in the body, it activates guanylyl cyclase, elevating cyclic GMP levels that relax vascular smooth muscle, thereby dilating veins and arteries to enhance myocardial blood flow and reduce cardiac workload. Approved by the FDA for acute relief and prophylaxis of angina attacks, it finds off-label applications in managing hypertensive emergencies, coronary spasms, heart failure with reduced ejection fraction (often combined with hydralazine), and esophageal spasms linked to conditions like GERD or eosinophilic esophagitis. Administered via sublingual tablets, sprays, patches, creams, or intravenous routes, nitroglycerin swiftly improves oxygen delivery to the heart, countering ischemia during physical exertion or acute episodes.