Evaluation of a sustained-release buccal nitroglycerin preparation in stable angina pectoris.

The efficacy of a 2.5 mg sustained-release buccal nitroglycerin preparation given 8-hourly in effort-induced stable angina pectoris was investigated by means of graded exercise testing in 15 patients. An initial double-blind crossover study, compared with a placebo (duration six days) was followed by a further 15-day open treatment period on the active drug. Exercise testing was carried out 2 and 7 h after tablet administration at the conclusion of active treatment in the double-blind phase, and 2 h after tablet administration at the conclusion of the open treatment phase. Workload and exercise duration were significantly increased and mean electrocardiographic ST segment depression and ST segment recovery time significantly reduced by buccal nitroglycerin in the initial phase of the study, and these improvements were maintained over the subsequent 15-day assessment period. Systolic blood pressure at rest was significantly decreased by active treatment; other haemodynamic parameters remained unchanged. The study demonstrated the efficacy of sustained-release buccal nitroglycerin in effort-induced stable angina pectoris, and an absence of (+) tolerance to the therapeutic effects of this mode of nitrate administration.