Nifedipine therapy for Prinzmetal's angina.

A case is described in which nifedipine, a new coronary vasodilator, was effective in relieving attacks of Prinzmetal's angina unresponsive to conventional therapy. The extreme frequency of the anginal attacks provided evidence that lower doses of nifedipine lost their effectiveness approximately 4 hours after administration. A month after initiation of nifedipine, nitrates were withdrawn since they had been ineffective in controlling the attacks. A myocardial infarction occurred immediately, presumably due to coronary spasm.