A Comparison of a Controlled Release (CR/ZOK) Formulation of Metoprolol, Once Daily, with Conventional Metoprolol Tablets, Twice Daily, in Mild to Moderate Hypertension

In a randomized double-blind multicenter study in 100 hypertensive patients, the effect of once daily (od) dosing with a new controlled release (CR/ZOK) formulation of metoprolol was compared with that of twice daily (bid) dosing with metoprolol conventional tablets. Eligible patients had a resting seated diastolic blood pressure (DBP) ≥ 95 mm Hg and 95 mm Hg) at the end of the first 4-week period. Approximately 40% of both groups received concomitant diuretic therapy throughout the study. The SBP, DBP and HR were reduced compared to baseline in both treatment groups after 4 and 8 weeks. After 4 weeks, 85% of the CR/ZOK group and 74% of the tablet group had DBP <95 mm Hg. After another 4 weeks, the corresponding figures were 93% and 93%. There was no statistically significant difference between the treatment groups in the decrease in either SBP, DBP or HR, nor was there any difference in the percentage of responders. Both treatments were equally well tolerated. In conclusion, the antihypertensive effect of once daily dosing (100–200 mg) with the new CR/ZOK formulation of metoprolol is as effective as that of twice daily dosing (50–100 mg) with conventional metoprolol tablets.