A comparison of the efficacy and safety of irbesartan/HCTZ combination therapy with irbesartan and HCTZ monotherapy in the treatment of moderate hypertension

This prospective, double-blind, parallel-group study randomized patients with moderate hypertension ( seated systolic blood pressure (SeSBP) 160-179mmHg when seated diastolic blood pressure (SeDBP) <110mmHg; or SeDBP 100-109mmHg when SeSBP <180mmHg) 3: 1: 1 to treatment with irbesartan 300mg/hydrochlorothiazide ( HCTZ) 25mg combination therapy (n = 328), irbesartan 300mg monotherapy ( n = 106) or HCTZ monotherapy 25mg ( n 104). Treatment was initiated at half dose, with forced titration to full dose after two weeks followed by ten further weeks' treatment. The primary efficacy variable was the mean reduction in SeSBP from baseline to week 8. Baseline characteristics were similar between groups, with mean baseline blood pressure approximately 162/98mm Hg; the mean age was 55 years. At week 8 there was a reduction in SeSBP of 27.1mmHg with irbesartan/HCTZ, compared with 22.1mmHg with irbesartan monotherapy (P = 0.0016) and 15.7mmHg with HCTZ (P<0.0001). Both the rate of decline and the total degree of decline achieved were greatest with irbesartan/HCTZ and least with HCTZ. A significantly greater percentage of patients reached a treatment goal of SeSBP <140mmHg and SeDBP <90mmHg by week 8 with irbesartan/HCTZ (53.4%), compared with irbesartan (40.6%; P = 0.0254) and HCTZ (20.2%; P<0.0001) alone. Treatment was well tolerated in all three-treatment groups with a slight increase in adverse events in the combination therapy group. In conclusion, irbesartan/HCTZ (300/25mg) is well tolerated and achieves rapid and sustained reductions in both systolic blood pressure and diastolic blood pressure in patients with moderate hypertension.