Comparison of labetalol, hydrallazine, and propranolol in the therapy of moderate hypertension.

The efficacy of labetalol, an alpha and beta adrenoceptor blocking drug, has been compared with that of placebo, of propranolol alone, of hydrallazine alone, and of hydrallazine plus propranolol in combination in a randomized double-blind, fixed-dose crossover trial. Labetalol (300 mg twice a day) was equally effective with propranolol (80 mg twice a day), and more effective than hydrallazine (50 mg twice a day) alone. The effect of labetalol was comparable with that of hydrallazine plus propranolol when the patient was standing, but less potent with the patient in the supine position. Side effects were few.