Efficacy of intermittent (eight hours off) transdermal nitrate therapy in stable angina

The efficacy of intermittent (16 h on/8 h off) transdermal nitrate therapy (0.4 mg/h) was assessed in 46 patients with chronic stable angina, all but one of whom were on concomitant beta-blocker and/or calcium antagonist therapy. The study was a randomised, double-blind placebo-controlled crossover with two consecutive 7-day treatment periods, conducted at two centres. Prior to entry into the study patients were screened for exercise test reproducibility and nitrate response. Patch efficacy was determined by maximal symptom limited treadmill stress testing (Bruce protocol) and subjective diary card data. Analysis of variance showed that active treatment significantly improved time to onset of angina (P < 0.001), time to 1 mm ST-segment depression (P < 0.001) and total exercise duration (P < 0.001) compared with placebo from 385.7, 310.8 and 458.1 s to 455.7, 385.2 and 497.1 s, respectively. Nitrate patch therapy significantly reduced diastolic and systolic blood pressures without significantly increasing resting heart rate. There was a marginal reduction in the incidence of angina attacks and sublingual nitroglycerine consumption during active treatment. We conclude that intermittent transdermal nitrate therapy significantly improves exercise tolerance in patients with chronic angina pectoris and that this improvement occurs in addition to conventional anti-anginal therapy.