For the management of acute angina, which medication is preferred for immediate relief?

Choice A rationale Metoprolol is a beta-blocker that reduces myocardial oxygen demand by decreasing heart rate, contractility, and blood pressure. While it is effective for long-term management and prevention of angina, it is not the preferred choice for immediate relief of an acute anginal attack due to its slower onset of action. Its primary role is prophylaxis. Choice B rationale Nitroglycerin is a potent vasodilator that works by relaxing vascular smooth muscle, primarily affecting veins, which reduces venous return (preload) and myocardial oxygen demand. It also dilates coronary arteries, increasing blood flow and oxygen supply to the heart muscle. Its rapid onset makes it the drug of choice for acute angina. Choice C rationale Amlodipine is a calcium channel blocker that works by inhibiting the influx of calcium into vascular smooth muscle and myocardial cells, causing vasodilation and reduced peripheral resistance. Although it is used for the long-term management of chronic stable angina, its onset of action is not rapid enough for immediate relief during an acute attack. Choice D rationale Aspirin is an antiplatelet agent that works by irreversibly inhibiting cyclooxygenase (COX) enzyme, preventing the formation of thromboxane A2. This reduces platelet aggregation and clot formation, which is crucial in preventing myocardial infarction in the setting of unstable angina, but it does not provide immediate relief from chest pain.