The evidence from this review suggests that there are no clinically meaningful BP lowering differences between available ARBs. The BP lowering effect of ARBs is modest and similar to ACE inhibitors as a class; the magnitude of average trough BP lowering for ARBs at maximum recommended doses and above is -8/-5 mmHg.  Furthermore, 60 to 70% of this trough BP lowering effect occurs with recommended starting doses. The review did not provide a good estimate of the incidence of harms associated with ARBs because of the short duration of the trials and the lack of reporting of adverse effects in many of the trials.
Matrix study of irbesartan with hydrochlorothiazide in mild-to-moderate hypertension.
The purpose of this study was to assess the safety and antihypertensive dose-response effects of irbesartan and hydrochlorothiazide (HCTZ) in patients with mild-to-moderate hypertension. After a 4- to 5-week single-blind placebo lead-in period, 683 patients with seated diastolic blood pressure (SeDBP) between 95 and 110 mm Hg were randomized to receive once-daily dosing with one of 16 different double-blind, fixed combinations of irbesartan (0, 37.5, 100, and 300 mg irbesartan) and HCTZ (0, 6.25, 12.5, and 25 mg HCTZ) for 8 weeks. The primary efficacy variable was the change from baseline in trough SeDBP after 8 weeks of therapy. Data were analyzed by response surface modeling. At Week 8, mean changes from baseline in trough SeDBP (mm Hg) ranged from -3.5 for placebo, -7.1 to -10.2 for the irbesartan monotherapy groups, -5.1 to -8.3 for the HCTZ monotherapy groups, and -8.1 to -15.0 for the combination groups. Irbesartan plus HCTZ produced additive reductions in both SeDBP and seated systolic BP, with at least one combination producing greater BP reduction than either drug alone (P < .001). All treatments were well tolerated; there were no treatment-related serious adverse events. Irbesartan tended to ameliorate the dose-related biochemical abnormalities associated with HCTZ alone. In conclusion, the combination of HCTZ in doses up to 25 mg with irbesartan, in doses up to 300 mg, is safe and produces dose-dependent reductions in BP.