964-15 Diuretic Therapy Improves Exercise Capacity in Patients with Angina but has no Effect on Nitrate Tolerance

Diuretics have been reported to prevent tolerance to the organic nitrates. Since diuretic therapy itself may have an anti-anginal effect, we carried out a study which examines the effect of diuretic therapy alone on exercise capacity in angina as well as its effect on nitrate tolerance.Methods12 patients with stable angina were studied. All had normal LV systolic function. None were hypertensive or had a history of CHF. Patients received a diuretic (HCTZ plus amiloride) or placebo for 10–14 days in a randomized, double-blind, cross-over trial. During the last 5–7 days of each treatment period they received continuous transdermal nitroglycerin (TGTN) 0.8 mg/hr in a single blind manner. Treadmill walking time (TWTl was assessed prior to the addition of TGTN (Day 1) to assess the effect of diuretic alone, on the first day of TGTN therapy (Day 2) and on the last day of TGTN therapy (Day 3). Exercise testing was performed at 0800, 1200 and 1600hrs on each of these days.ResultsDiuretic therapy caused an increase in TWT on all 3 study days. HR and systolic BP were higher at peak exercise during diuretic therapy as compared to placebo (data not shown). Diuretic therapy did not prevent the development of tolerance during continuous TGTN therapy.*p=<0.05 vs placebo (cross over analysis of Hills and Armitage).ConclusionsDiuretic therapy has significant anti-anginal effects and improves exercise capacity in patients with stable angina. Diuretics appear to have no effect on the development of tolerance to continuous TGTN therapy as assessed by treadmill exercise testing