A client is receiving sublingual nitroglycerin (Nitrostat). Which instruction should the nurse give?

• A. Discard unused pills if bottle opened for six months
• B. Take a second dose ten minutes after first dose
• C. Do not take this medication if your heart rate is irregular
• D. Chew the tablet well to increase the therapeutic effects

Answer: (A)

Potency of sublingual nitroglycerin tablets is time- or exposure-dependent, so they must be used with a fresh supply after the bottle has been opened for a certain period. Replacing the bottle after six months of opening helps ensure the medication delivers the intended effect when a patient needs it for chest pain. Proper storage—keep the bottle tightly closed, in a dark place at room temperature, and away from moisture—also helps preserve potency.

Taking a second dose ten minutes after the first isn’t aligned with standard guidance, which uses a five-minute interval between doses and allows up to three doses in about 15 minutes if pain persists. So waiting ten minutes for the second dose could delay relief.

Ignoring heart-rate status isn’t a correct safety signal either; an irregular heart rate isn’t a contraindication to nitroglycerin by itself, though the medication can cause dizziness or hypotension, and certain conditions or drug interactions would alter its use.

Chewing the tablet is not appropriate because nitroglycerin is intended to be absorbed under the tongue to act quickly; chewing diminishes this rapid sublingual route and reduces effectiveness.