A multicenter, randomized, double-blind, parallel-group trial of the antihypertensive efficacy and tolerability of a combination of once-daily Losartan 100mg/hydrochlorothiazide 12.5 mg compared with Losartan 100-mg monotherapy in the treatment of mild to severe essential hypertension

Background: Because patients with hypertension may require > 1 antihypertensive agent to control blood pressure (BP), physicians often prescribe a fixed combination of antihypertensive medications. Objective: This study evaluated the effect of adding low-dose hydrochlorothiazide 12.5 mg (HCTZ12.5) to high-dose losartan 100 mg (L100) in patients with hypertension whose BP was inadequately controlled with L100 monotherapy. Methods: Enrolled in this multicenter, randomized, double-blind, parallel-group, filter study were patients aged >= 18 years with a mean trough sitting diastolic BP (SiDBP) of 95 to 120 mm Hg. Patients were treated with L100 QD for 4 weeks. Patients who did not achieve adequate BP control were randomly assigned to receive L100/HCTZ12.5 or L100 QD for 6 weeks. The primary efficacy measure was the mean change in trough SiDBP from baseline in the 2 groups. Responders were defined as patients with a mean trough SiDBP of < 90 min Hg or patients who had a >= 10-mm Hg decrease in mean trough SiDBP. Results: Demographic characteristics were similar between treatment groups. The patients randomized to the double-blind treatment period were mostly white (65.1%) and male (57.5%), with a mean age of 53.8 years. The mean (SD) duration of hypertension at baseline was 9.7 (8.5) years. The proportion of patients previously treated with antihypertensive therapy was 76.7%. Of the 367 patients enrolled in the L100 filter period, 292 patients had BP inadequately controlled with 1,100 monotherapy and were randomized to receive L100 (n = 145) or L100/HCTZ12.5 (n = 147). At week 6 after randomization, mean trough SiDBP was significantly lower in the L100/HCTZ12.5 group than in the L100 group (-8.3 vs -5.2, respectively; P < 0.001). The between-group difference was -3.0 mm Hg (95% CI, -4.6 to -1.40; P < 0.001), and the proportion of responders was significantly greater in the L100/HCTZ12.5 group than in the L100 group (63.0% vs 44.4%; P < 0.001). The incidence of adverse events (AEs) occurring in > 2% of patients during the double-blind period was similar for both groups. AEs occurring in the L100 group and the L100/HCTZ12.5 group included respiratory tract infection (6.2% vs 3.4%, respectively), dizziness (2.1% vs 0.7%), and headache (0.7% vs 3.4%). Conclusions: After 6 weeks of therapy, L100/ HCTZ12.5 was associated with greater antihypertensive efficacy than L100, as measured by the change in mean trough SiDBR The percentage of responders was significantly greater in the L100/HCTZ12.5 group than in the L100 group. (Clin Ther. 2006;28: 1639-1648) Copyright (c) 2006 Excerpta Medica, Inc.