Comparative efficacy of atenolol and labetalol in essential hypertension--a double blind cross over trial.

In a double blind cross-over drug trial, antihypertensive effects (resting and after dynamic exercise) of atenolol and of labetalol were studied in 20 patients of mild to moderate essential hypertension. Both drugs exhibited almost equal antihypertensive response, and were well tolerated. Haemodynamic variables (HR, SBP, DBP and RPP), both at rest and after maximal tread mill exercise, were significantly altered (P less than 0.001) by both drugs. Exercise capacity was observed to be marginally improved by atenolol. Although the antihypertensive effect, when compared between the two drugs, was not statistically significant, individual suitability or comparison revealed a preference for atenolol in 17 patients and for labetalol in 3 patients.