Pharmacology · single question
A patient with chest pain is given sublingual nitroglycerin. What is its mechanism of action?
Show answer and explanation
Correct answer: A. Releases nitric oxide, activating guanylyl cyclase (↑cGMP → vasodilation)
- A. Correct. Nitroglycerin is metabolized to nitric oxide, which activates guanylyl cyclase, raising cGMP and relaxing vascular smooth muscle (especially venous), reducing preload and cardiac oxygen demand.
- B. cAMP elevation describes beta-agonists/PDE inhibitors, not nitrates.
- C. COX inhibition describes NSAIDs.
- D. Direct calcium-channel blockade describes CCBs; nitrates act via the NO/cGMP pathway.