Nitroglycerin prophylaxis in angina pectoris. Effect of sustained release nitroglycerin capsules on anginal frequency and exercise capacity.

Since the pharmacological effects of sublingual nitroglycerin are of short duration, attempts have been made over a number of years to prolong the activity of nitroglycerin by various means, viz. : (1) topical applications of nitroglycerin ointments, relying upon percutaneous absorption; (2) changes in chemical structure leading to such derivatives as isosorbide dinitrate or pentaerythritol tetranitrate; and (3) development of pharmaceutical preparations devised to disintegrate slowly, thus releasing the active substance over a long period. The purpose of the present study was to determine the effects of such a sustained-release nitroglycerin preparation on the frequency of painful paroxysms and on exercise capacity in patients with angina pectoris. In a double-blind trial comparing the preparation with a placebo 25 patients were observed during 24 weeks. The active substance significantly reduced the number of anginal attacks and increased exercise capacity in all cases. It would therefore seem that sustained-release nitroglycerin capsules deserve to have a place in the treatment of angor pectoris. However, further studies involving a larger number of patients are required to support these conclusions.