Nicorandil is used in refractory angina. Its dual mechanism of action includes:
- A Nitrate-like action (nitric oxide donation) combined with ATP-sensitive potassium channel opening ✓
- B Beta-1 blockade and dihydropyridine-type calcium channel blockade
- C Sinus node If current inhibition and coronary vasodilation via alpha blockade
- D ACE inhibition and direct coronary artery vasodilation
Correct answer: A. Nitrate-like action (nitric oxide donation) combined with ATP-sensitive potassium channel opening
Explanation
Nicorandil uniquely combines a nitrate moiety (releases nitric oxide, activating guanylyl cyclase, increasing cGMP, causing vasodilation — predominantly venodilation) with an ATP-sensitive potassium (KATP) channel-opening action that hyperpolarizes vascular smooth muscle, causing arterial vasodilation. This dual mechanism provides both preload and afterload reduction and may confer direct cardioprotective (ischaemic preconditioning-like) effects. It avoids nitrate tolerance due to the K-channel component.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
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Written and medically reviewed by the StethoPrep medical team.