The efficacy and tolerability of enalapril in a formulation with a very low dose of hydrochlorothiazide in hypertensive patients resistent to enalapril monotherapy.

The antihypertensive efficacy and tolerability of formulations of enalapril and low (12.5 mg) and very low (6 mg) doses of hydrochlorothiazide (HCTZ) were compared with enalapril and placebo. Four hundred and two patients with mild to moderate essential hypertension were treated with 20 mg enalapril for 8 weeks. Patients (n = 296) with persistent supine diastolic blood pressure > 95 mm Hg after enalapril monotherapy were randomized to receive enalapril/placebo (group I), 6 mg enalapril/HCTZ (group II), or 12.5 mg enalapril/HCTZ (group III) for another 8 weeks in a double-blind design. The mean reductions in blood pressure were significantly larger in groups II and III compared to group I, 7.3 (95% CI, -9.0; -6.2), 7.7 (-9.2;-6.3), and 4.1 (-5.9;-2.9) mm Hg, respectively P < .01 for groups II and III compared to group I). No difference in side effects was observed between the three groups. A very low dose of 6 mg HCTZ acts synergistically when given together with enalapril, but is devoid of adverse metabolic effects.