A comparative study of three beta 1-adrenoreceptor blocking drugs with different degree of intrinsic stimulating activity (metoprolol, practolol and H 87/07) in patients with angina pectoris

Abstract

Three beta1-selective beta-blocker (metoprolol, practolol and H 87/07) were compared in 29 patients with stable angina pectoris. The main pharmacological difference between the three beta-blockers was their intrinsic stimulating activity (I.S.A.), metoprolol being devoid of I.S.A., practolol having moderate I.S.A. and H 87/07 having high I.S.A. Each drug was given in randomized order and the length of each cross-over period was 2 weeks. Daily activity was measured by an automatic step-counter, and subjective symptoms and nitroglycerin consumption were registered on a diary-card. Objective data, such as ECG changes and exercise capacity, were obtained by bicycle ergometer tests performed at the end of each period. At rest, the heart rate was significantly lower on metoprolol than on practolol or H 87/07. During exercise, the heart rate was significantly higher on H 87/07 than on practolol or metoprolol. No other haemodynamic differences were found between the three beta-blockers. No differences were found between the three test periods with regard to daily activity, expressed as the number of steps walked, while on the beta-blocker with high I.S.A., H 87/07, the attack rate and nitroglycerin consumption were significantly higher than when the patients were on metoprolol and practolol. No difference was found between the three beta-blockers with regard to total work or exercise time until 1 mm of S-T segment depression. Except for one patient who experienced a severe exanthema on practolol, the three beta-blockers were equally well tolerated.