Double-blind trial comparing labetalol with atenolol in the treatment of systemic hypertension with angina pectoris

Some theoretical arguments suggest that added vasodilation could be beneficial in the management of patients with systemic hypertension and angina pectoris. Ten patients were studied in a double-blind crossover trial in which the severity of hypertension and angina pectoris was monitored. The initial run-in period of 2 to 6 weeks consisted of therapy with fixed-dose atenolol, 100 mg once daily, a thiazide diuretic drug, and any other agents required to control the hypertension. Patients were then randomized for 4 weeks to active atenolol plus 2 tablets of labetalol placebo, or active labetalol (200 mg twice daily) plus atenolol placebo, then crossed over and then changed back to active atenolol without labetalol placebo; the observers were unblinded in the last period. Labetalol and atenolol were equivalent in control of blood pressure at rest, exercise tolerance and use of nitroglycerin; however, heart rates at rest and during exercise were higher with labetalol (p < 0.01), whereas the heart rate-blood pressure product at the end of the exercise test was unchanged with labetalol. The higher heart rates for the same antianginal efficacy may give an advantage to labetalol treatment in some patients. Conversely, atenolol is cardioselective, hydrophilic, and can be given as a single daily dose. Thus, each agent has some advantages in the therapy of patients with hypertension and effort angina.