Increased exercise tolerance after nitroglycerin oral spray: a new and effective therapeutic modality in angina pectoris.

Abstract

The prophylactic antianginal efficacy of nitroglycerin (NTG) oral spray was assessed in 20 patients with angiographically documented coronary disease and stable angina pectoris. The evaluation was by a randomized crossover trial involving treadmill exercise testing. On study day 1, a control treadmill exercise test was performed, followed 30 minutes later by a second exercise test 2 minutes after administration of either placebo (group A, 10 patients) or NTG spray 0.8 mg (group B, 10 patients). One week later, on study day 2, the patients again underwent control treadmill exercise testing followed by a second exercise test after either NTG spray (group A) or placebo (group B). NTG spray delayed the onset of anginal pain during exercise by a mean of 100 +/- 64 seconds (p less than 0.001) in 13 patients and prevented pain entirely in seven. Placebo did not significantly delay the appearance of angina and prevented chest pain in only one patient. NTG spray increased treadmill exercise duration by 31% before the onset of angina (p less than 0.001); placebo did not significantly alter the duration of exercise. NTG spray abolished in six patients and delayed in 14 patients the onset of exercise-induced ST-segment depression of 1 mm (p less than 0.001). Patients achieved a higher heart rate at peak exercise with NTG spray, and yet the maximal exercise-induced ST-segment depression of 2.1 +/- 1.0 mm during the control study declined to 1.3 +/- 0.9 mm on NTG spray (p less than 0.001). Placebo had no effect on exercise ST-segment depression. These data indicate that the oral NTG spray is an effective prophylactic for exercise-induced angina.