A nurse is providing teaching to a client who has a new prescription for nitroglycerin topical ointment. Which of the following instructions should the nurse include in the teaching?

Rationale: A. "Apply the ointment to the skin every 4 hr.": Nitroglycerin topical ointment is applied every 6 to 8 hours, depending on the provider's instructions. Applying it every 4 hours may increase the risk of side effects such as hypotension or tolerance due to excessive dosing frequency. B. "Spread the ointment in a thin, even layer.": The medication should be applied in a thin, consistent layer to allow for proper absorption through the skin. The dose is usually measured and spread using applicator paper, avoiding rubbing or massaging it in. C. "Apply the ointment to the forearm.": The preferred application sites are hairless areas of the chest, back, or upper arms. The forearm is not typically used due to variability in absorption and the presence of thinner skin and more movement. D. "Massage the ointment into the skin.": Nitroglycerin ointment should never be massaged into the skin. Massaging can lead to unpredictable absorption rates and an increased risk of hypotension or headache due to rapid systemic absorption.