Comparative antihypertensive effectiveness of once-daily mibefradil and diltiazem CD. Mibefradil Hypertension Study Group.

This multicenter, double-masked, randomized, forced-titration, parallel-group trial was designed to determine whether we could confirm the results of a previous trial that demonstrated a significantly greater antihypertensive effect for mibefradil compared with diltiazem CD. Two hundred thirty-nine patients with uncomplicated mild-to-moderate essential hypertension and a baseline sitting diastolic blood pressure (SDBP) between 95 and 114 mm Hg were randomized to receive once-daily treatment with mibefradil 50 mg (n = 119) or diltiazem CD 180 mg (n = 120). After 4 weeks of treatment, all patients underwent forced titration to mibefradil 100 mg or diltiazem CD 360 mg for an additional 8 weeks. After 12 weeks of active treatment, the mean reduction from baseline in trough SDBP was significantly greater with mibefradil than with diltiazem CD (-14.3 +/- 6.6 mm Hg vs -11.7 +/- 7.4 mm Hg, respectively). In addition, significantly more patients receiving mibefradil had a decrease in SDBP > or = 10 mm Hg or a decrease to < or = 90 mm Hg by week 12 than did patients receiving diltiazem CD (82% vs 72%, respectively). The tolerability of mibefradil and diltiazem CD were comparable, with similar percentages of patients in both groups reporting at least one adverse event (21% vs 22%, respectively) that was considered to be at least remotely related to the study drug. The results of this study confirm those of the previous trial. Once-daily treatment with mibefradil 100 mg is significantly more effective than diltiazem CD 360 mg in lowering both diastolic and systolic blood pressure. Both drugs are well tolerated.