Sustained release metoprolol: a comparison with conventional formulation in the treatment of hypertension.

Thirty patients with essential hypertension (WHO Stage I or II) completed a double blind crossover trial in which they received metoprolol as monotherapy as either a slow release formulation of 200 mg once daily or a conventional formulation of 100 mg bd. Duration of treatment was six weeks on each preparation, given in randomised order. Mean values of resting blood pressure and heart rate, measured 22 to 24 hours after the daily dose of the SR formulation or 12-14 hours after the second dose of the conventional form were significantly lower than pretreatment levels. The two treatments were equally effective and equally well tolerated.