A randomised, double-blind comparison of the angiotensin II receptor antagonist, irbesartan, with the full dose range of enalapril for the treatment of mild-to-moderate hypertension.

Objective: To compare the anti-hypertensive efficacy, safety, and tolerability of irbesartan with those of the full dose range of enalapril in patients with mild-to-moderate hypertension.

Design And Methods: A total of 200 patients were randomised to irbesartan 75 mg or enalapril 10 mg (once daily). Doses were doubled at Weeks 4 and/or 8 if seated diastolic blood pressure (DBP) was > or = 90 mm Hg. Trough blood pressure was measured after completion of a 4- to 5-week placebo lead-in period and again after 2, 4, 8, and 12 weeks of treatment.

Main Outcome Measures: Efficacy was evaluated by determining the change from baseline in trough seated blood pressure and the proportion of patients normalised (seated DBP <90 mm Hg) at Week 12. Safety and tolerability were assessed by adverse events reported by physicians, by patients in response to a specific-symptoms questionnaire, by open-ended questioning of patients by physicians, and by clinical laboratory evaluations.

Results: Both treatments significantly lowered blood pressure with no significant difference in efficacy between treatment groups. At Week 12, the percentage of patients titrated to either enalapril 40 mg or irbesartan 300 mg was 24% and 28%, respectively. The frequency of overall adverse events was similar in both groups. The incidence of cough in the enalapril and irbesartan groups was 17% and 10%, respectively. In contrast to other AII receptor antagonists, there was no change in uric acid concentrations with irbesartan.

Conclusions: Irbesartan was as effective as the full dose range of enalapril. Irbesartan also demonstrated an excellent tolerability profile.