6. Which of the following therapies is not indicated in patients with angina from coronary vasospasm?

A. Dihydropyridine calcium channel blockers (amlodipine, nifedipine)

B. Non-dihydropyridine calcium channel blockers (diltiazem, verapamil)

C. Beta-blockers (atenolol, metoprolol)

D. Long acting nitrates (isosorbide mononitrate, isosorbide dinitrate)

When arterial tone is suddenly increased, coronary vasospasm can occur resulting in angina. This is also known as Prinzmetal's Angina or Variant Angina. Coronary arteries are angiographically normal, but vasospasm can be induced by ergonovine or acetylcholine infusion. Treatment is with dihydropyridine calcium channel blockers. Beta-blockers should be avoided since this leads to “unopposed alpha agonism” which worsens vasoconstriction. Circulating catecholamines will agonize alpha receptors more easily if the beta-receptors are occupied by a beta-blocker.