Valsartan/hydrochlorothiazide is effective in hypertensive patients inadequately controlled by valsartan monotherapy.

Objective: This double-blind parallel-group randomized trial compared the efficacy and safety of fixed combination valsartan 160 mg/hydrochlorothiazide 12.5 mg (Val 160/HCTZ 12.5) once daily (o.d.) and Val 160/hydrochlorothiazide 25 mg (Val 160/HCTZ 25) o.d. vs Val 160 o.d. monotherapy in patients with mild-to-moderate essential hypertension not adequately controlled with valsartan monotherapy.

Method: A total of 2002 patients whose BP was inadequately controlled with 4 weeks of Val 160 mg o.d. monotherapy were randomized to treatment for 8 weeks with Val 160 (n = 666), Val 160/HCTZ 12.5 (n = 670) or Val 160/HCTZ 25 (n = 666).

Results: Active treatment significantly reduced BP in all groups over the 12 weeks of the study (p < 0.001). The greatest reductions were achieved with Val 160/HCTZ 25. Reductions were 10.8, 12.8 and 14.2 mmHg (sitting diastolic blood pressure) and 15.7, 19.4 and 21.8 mmHg (sitting systolic blood pressure), for the Val 160, Val 160/HCTZ 12.5 and Val 160/HCTZ 25 groups, respectively. Responder rates were high in all groups (49%, 62% and 68%). In elderly patients (> or = 65 years) responder rates of 70% were achieved with Val 160/HCTZ 25. All treatments were well tolerated, in all patient groups.

Conclusions: The combination of Val 160 plus HCTZ 12.5 or HCTZ 25 provides effective and well-tolerated treatment in patients inadequately controlled after 4 weeks of monotherapy. In elderly patients a responder rate of 70% was achieved with Val 160/HCTZ 25.