Efficacy and Safety of Olmesartan Medoxomil 40 mg/Hydrochlorothiazide 12.5 mg Combination Therapy versus Olmesartan Medoxomil 40 mg Monotherapy in Patients with Moderate to Severe Hypertension: A Randomized, Double-Blind, Parallel-Group, Multicentre, Multinational, Phase III Study

Background Current hypertension guidelines recommend using two antihypertensive agents when blood pressure (BP) control is not achieved with one single agent. Objective This study was designed to assess the antihypertensive benefit of the olmesartan medoxomil 40 mg/hydrochlorothiazide (HCTZ) 12.5 mg combination versus olmesartan medoxomil 40 mg monotherapy in patients with moderate to severe hypertension. Methods This was a randomized, double-blind, parallel-group, up-titration, multicentre, multinational, phase III study. Following a 2-week single-blind placebo run-in phase, 846 hypertensive patients with mean seated systolic BP (SeSBP) of 160–200 mmHg and mean seated diastolic BP (SeDBP) of 100–120 mmHg were randomized (1:2 ratio) to receive double-blind treatment with olmesartan medoxomil 40 mg or olmesartan medoxomil 40 mg/HCTZ 12.5 mg for 8 weeks (phase A). At week 8, patients not reaching BP goal (