A nurse is teaching a client who has angina pectoris about starting therapy with SL nitroglycerin tablets. The nurse should include which of the following instructions regarding how to take the medication?

A. "Take this medication after each meal and at bedtime.”: Sublingual (SL) nitroglycerin is a rapid-acting nitrate used PRN (as needed) for acute attacks. Long-acting nitrates (like isosorbide mononitrate) are taken on a schedule, but not SL tablets. B. "Take one tablet at the first indication of chest pain.”: The goal of therapy is to maximize oxygen supply to the heart muscle immediately. The client should stop activity and place one tablet under the tongue as soon as pain begins. C. "Take one tablet every 15 min during an acute attack.”: The standard protocol is to take one tablet every 5 minutes for a maximum of 3 doses. Waiting 15 minutes between doses would delay necessary vasodilation and relief. If pain is not relieved after the first dose (after 5 minutes), the client should call 911. D. "Take this medication with 8 ounces of water.”: Nitroglycerin is given via the sublingual route (dissolved under the tongue) for rapid absorption into the bloodstream. Swallowing it with water would destroy much of the medication in the stomach (first-pass effect) and render it ineffective for acute pain.