The client is experiencing an acute onset of angina. The nurse would most likely administer which medication?

In the context of acute angina, the most appropriate medication to administer is Nitrostat, which is a sublingual form of nitroglycerin. This medication acts quickly to relieve angina by dilating blood vessels, which reduces the heart's workload and improves blood flow to the heart muscle.

Nitrostat is specifically designed for rapid relief due to its quick onset of action, making it the first-line treatment during an acute angina episode. Patients experiencing acute angina typically need immediate relief from their symptoms, and the sublingual administration allows for rapid absorption into the bloodstream.

In contrast, the other medications listed have different mechanisms or are typically used for longer-term management rather than immediate symptom relief. Procardia (nifedipine) and Norvasc (amlodipine) are calcium channel blockers that are effective for angina prevention but not suitable for acute episodes due to their delayed onset. Nitro-Dur is a transdermal patch form of nitroglycerin, which is also not ideal for acute situations as it provides a slower, sustained release of medication rather than immediate relief.