The effect of metoprolol --a new selective adrenergic beta1-receptor blocking agent-- in mild hypertension.

Metoprolol, a new selective adrenergic beta1-receptor blocking drug, has been compared to placebo in a series of 24 women who previously had taken alprenolol and propranolol during a cross-over study. Blood pressure (BP) and heart rate (HR) were significantly reduced during metoprolol treatment compared to placebo. The occurrence of side-effects was similar during treatment with metoprolol and placebo. After the cross-over study the patients continued on metoprolol for more than two years, except for short periods on placebo or propranolol. During this follow-up period BP remained at a similar level when the metoprolol dose was unchanged. Dose reduction (from 50 or 100 mg t.i.d. to 50 or 100 mg b.i.d.) caused no, or only a very slight, increase in BP. No side-effects were reported during long-term treatment.