Metoprolol administered once daily in the treatment of hypertension. A double-blind crossover comparison between conventional tablets and metoprolol Durules.

The effect of metoprolol, a beta1-selective receptor blocking agent without intrinsic stimulating activity, on blood pressure, pulse and plasma concentration 2 and 24 h after dose intake and on working capacity and perceived exertion 2 h after dose intake was investigated when given as 100 mg and 200 mg conventional tablets or 200 mg slow-release tablets (Durules) once daily, long-term, to 20 patients with primary (essential) hypertension. Metoprolol 100 mg and 200 mg once daily effectively lowers blood pressure over a 24-h period, and 200 mg Durules once daily gives beta-receptor blockade for 24 h. Peak plasma concentration 2 h after dose intake and individual variations in plasma concentrations are reduced on 200 mg Durules compared with 200 mg conventional tablets. Working capacity is not reduced, though perceived exertion and leg fatigue seem to be slightly increased with metoprolol, especially 200 mg conventional tablets.