PLACEBO-CONTROLLED COMPARISON OF THE EFFICACY AND TOLERABILITY OF ONCE-DAILY MOXONIDINE AND ENALAPRIL IN MILD-TO-MODERATE ESSENTIAL-HYPERTENSION

Objectives To compare the antihypertensive efficacy and tolerability o f the imidazoline I, receptor agonist moxonidine, a centrally acting a ntihypertensive, with the angiotensin converting enzyme inhibitor enal april. Design An 8-week, double-blind, randomized, placebo-controlled study involving 140 outpatients with mild-to-moderate essential hypert ension. Methods Outpatients with WHO stage I or II hypertension were e nrolled in the study, After a 4-week placebo-controlled stabilization phase patients were allocated randomly to placebo, 0.2 mg moxonidine o nce a day or 5 mg enalapril once a day for 2 weeks. Dosages were then doubled to 0.4 mg moxonidine once a day or 10 mg enalapril once a day for a further 6 weeks, Blood pressure responses to therapy were measur ed by conventional office techniques and by 24 h ambulatory blood pres sure monitoring, Results The mean reduction in sitting blood pressure with moxonidine was similar to that with enalapril (19.5 +/- 16.0/12.3 +/- 8.7 versus 18.9 +/- 13.7/11.8 +/- 8.0 mmHg) and significantly sup erior to that with placebo (-4.6 +/- 12.3/-4.7 +/- 6.8 mmHg, P < 0.001 ). In addition to reducing blood pressure during conventional measurem ents, moxonidine administration reduced blood pressure throughout 24 h ambulatory measurements, The trough :peak ratio for moxonidine was 0. 7. Both moxonidine and enalapril were tolerated well, Conclusions Moxo nidine is an effective and well-tolerated antihypertensive, at least a s good as other established forms of antihypertensive medication. The trough:peak ratio of 0.7 indicates that the drug will be effective adm inistered once a day.