Labetalol, a cross-over double blind controlled trial.

20 patients (12 female) with moderately severe essential hypertension [blood pressure during placebo treatment 181 +/- 6 (systolic), 107 +/- 3 (diastolic)] completed a double-blind, cross-over dose-titrated comparison of labetalol and methyldopa. Both drugs reduced lying and standing arterial blood pressure to a similar extent, although only labetalol reduced heart rate. Compliance was high (greater than 95%) with both drugs, and the incidence of subjective adverse effects was similar.