RESUMO
Ten male patients with chronic stable angina pectoris completed a randomized, double-blind cross-over study, with matched placebo run-in period (P), to compare the effects of a long-acting preparation of propranolol (LA, 160 mg once a day) with that of conventional propranolol (CP, 40 mg four times a day) each given for 14 days. Response was assessed by symptom-limited bicycle ergometry, degree of ST segment depression, daily anginal attack rate and glyceryl trinitrin consumption (GTN). Heart rate and ventricular extra-systolic frequency (VES) were recorded by 24 h Holter monitor. Bicycle ergometry was performed and a trough blood sample taken for propranolol estimation on day 14 prior to the morning dose. Both formulations increased total work capacity (P 3412, LA 4095, CP 3697 kpm/min), reduced rate-pressure product (P 21896, LA 16011, CP 15609 mm Hg beats/min), and degree of ST segment depression (P 4.53, LA 2.48, CP 2.43), but without differences between the formulations. Daily anginal attack rate was reduced from 30 (placebo) to 7.5 (CP) and 14.5 (LA) (P less than 0.05 between treatment groups). There was a reduction in daily GTN consumption by both treatments. The heart rate and total number of VESs during 24 h was similar in the two treatment groups and was reduced in comparison with placebo. Both formulations were well tolerated. Long-acting propranolol is an effective and well-tolerated alternative to conventional propranolol in the treatment of chronic stable and stress-induced angina, and in reducing VES frequency.
