A nurse is teaching a client who has a new prescription for nitroglycerin sublingual tablets for treating angina. Which of the following instructions should the nurse include in the teaching?

A. “Call 911 if pain persists 30 minutes after taking one tablet” is incorrect. The client should call 911 if chest pain persists after taking three doses of nitroglycerin at 5-minute intervals, not 30 minutes. B. “Take a tablet every 10 minutes until the pain subsides” is incorrect. The correct instruction is to take one tablet every 5 minutes, up to three tablets, and seek emergency help if the pain does not subside. C. “Place the tablet under the tongue until dissolved” is correct. Sublingual nitroglycerin should be placed under the tongue to dissolve, allowing for rapid absorption and relief of angina. D. “Store the tablets in a refrigerator in a plastic container” is incorrect. Nitroglycerin tablets should be stored at room temperature in their original glass container to maintain potency.