Which medication would likely be contraindicated in a patient with severe aortic stenosis?

In the context of severe aortic stenosis, nitroglycerin is contraindicated primarily due to its vasodilatory effects, which can lead to significant hypotension. In patients with severe aortic stenosis, the heart relies on maintaining adequate systemic vascular resistance to ensure sufficient blood flow through the narrowed aortic valve. When nitroglycerin causes vasodilation, there is a reduction in preload, which can compromise cardiac output even further due to the fixed obstruction at the level of the aortic valve. This reduction can precipitate symptoms of heart failure or reduce perfusion to vital organs.

In contrast, the other medications listed may not pose the same level of risk in this scenario. Amlodipine, a calcium channel blocker, can be used cautiously as it manages angina by reducing myocardial oxygen demand without significantly affecting preload. Nadolol, a beta-blocker, is generally safe as it can reduce heart rate and myocardial oxygen consumption without direct vasodilatory effects that would lead to hypotension in the face of aortic stenosis. Isosorbide dinitrate, although also a nitrodilator, is sometimes used in combination with other agents but can carry risks similar to nitroglycerin under certain conditions, depending on