The hypotensive effect of a single daily dose of labetalol: a preliminary study

We analyzed the efficacy of a single daily dose of labetalol (300 mg) administered at 9 a.m. in six inpatients suffering from medium-severe hypertension. The study was conducted on 3 consecutive days, during which the patients were on labetalol, placebo, and non-treatment (control) according to a trial design of the Latin square type, balanced for residual effects. The hypotensive effect of labetalol manifests itself between hours 1 and 2 after administration of the drug. The systolic and diastolic blood pressure values always proved lower after labetalol as compared to placebo and non-treatment (control) as well as to the average of the latter two values (placebo + control) divided by 2. No side effects were detected.