Controlled comparison of labetalol and propranolol in the management of severe hypertension.

1 Labetalol, a new hypotensive drug combining alpha- and beta-adrenoreceptor antagonist properties, has been compared with propranolol in the treatment of severe hypertension (blood pressure 190/115-249/139 mmHg) in a double-blind trial lasting 14 weeks. Additional diuretic therapy was given to both groups of patients. 2 Both drugs caused an effective reduction in blood pressure, bbut labetalol caused a greater fall in pressure in the standing position and after exercise. Two groups of nine patients have each completed the trial so far. Group average pressures for the last 3 weeks of treatment were: for labetalol 137/87 supine, 121/84 standing, and 117/78 mmHg after exercise; and for propranolol, 138/87 supine, 132/93 standing, and 133/94 mmHg after exercise. 3 Group average heart rates were lower in all three positions for those patients treated with propranolol compared with labetalol. 4 The average final dose ratio for labetalol: propranolol was 1.44:1 (w/w). 5 Labetalol initially induced a number of side-effects, predominantly related to alpha-adrenoreceptor blockade, which disappeared by the end of the trial. 6 Labetalol, in conjunction with diuretic therapy, was at least as effective as propranolol in lowering blood pressure in patients with severe hypertension.