Which of the following is a side effect of nitroglycerin?

• A. Hypotension
• B. Headache
• C. Burning sensation under tongue
• D. Syncope

Answer: (C)

Sublingual nitroglycerin often produces a brief burning or tingling sensation under the tongue as the tablet rapidly dissolves in the mouth. This local, route-specific effect is a well-known and common side effect of sublingual nitrates and signals the medication is being absorbed.

Nitroglycerin also causes vasodilation throughout the body, which can lead to headaches and lowered blood pressure, and in some cases dizziness or syncope with significant hypotension. But the burning sensation under the tongue is the characteristic, commonly reported effect tied directly to the sublingual administration, making it the best answer in this context.