Antihypertensive Efficacy and Safety of Fixed-Dose Combination Therapy with Losartan plus Hydrochlorothiazide in Japanese Patients with Essential Hypertension

A randomized, double-blind, placebo-controlled, parallel-group multicenter study was conducted to evaluate the antihypertensive efficacy and safety of 8-week treatment with one of three fixed-dose combinations—losartan 50 mg plus hydrochlorothiazide 12.5 mg, losartan 50 mg plus hydrochlorothiazide 6.25 mg, or losartan 25 mg plus hydrochlorothiazide 6.25 mg—in comparison with those of hydrochlorothiazide 12.5 mg alone, losartan 50 mg alone, or placebo in Japanese patients with essential hypertension. Significant reductions in sitting diastolic blood pressure (DBP) and systolic blood pressure (SBP) were seen in all three combination groups compared with the placebo group (each p<0.001). The greatest reductions in DBP and SBP were observed in the losartan 50 mg plus hydrochlorothiazide 12.5 mg group (12.7 and 18.0 mmHg, respectively). The reductions in the losartan 50 mg plus hydrochlorothiazide 12.5 mg group were significantly greater (each p<0.001) than those in the placebo group and each of the monotherapy groups. There were no significant differences in the incidences of clinical and laboratory drug-related adverse events between any of the combination groups and the placebo group. All combination groups showed improved hypokalemia and hyperuricemia compared to the hydrochlorothiazide 12.5 mg group. These results demonstrated that once-daily, fixed-dose combination therapy with losartan 50 mg plus hydrochlorothiazide 12.5 mg is well tolerated and more efficacious in lowering DBP and SBP than monotherapy in Japanese hypertensive patients.