Adding Hydrochlorothiazide to Olmesartan/Amlodipine Increases Efficacy in Patients With Inadequate Blood Pressure Control on Dual‐Combination Therapy

This randomized, parallel‐group study in patients inadequately controlled on olmesartan medoxomil/amlodipine ( OLM / AML ) 40/10 mg assessed the effects of adding hydrochlorothiazide ( HCTZ ) 12.5 mg and 25 mg, using seated blood pressure (Se BP ) measurements and ambulatory blood pressure ( BP ) monitoring. Enrolled patients were screened and tapered off of therapy if required. All patients received OLM / AML 40/10 mg and those with mean seated BP (Se BP ) ≥140/90 mm Hg after 8 weeks (n=808) were randomized (1:1:1) to continue with  OLM / AML 40/10 mg or receive OLM / AML / HCTZ 40/10/12.5 or 40/10/25 mg for a further 8 weeks. The primary endpoint was the change in seated diastolic BP (Se DBP ) from the start to the end of the randomized treatment period. The addition of HCTZ 25 mg significantly reduced Se DBP (−2.8 mm Hg; P <.0001), lowered seated systolic BP (Se SBP ) and ambulatory DBP and SBP , and improved BP goal rates. In patients uncontrolled on OLM / AML 40/10 mg, adding HCTZ led to further BP reductions, particularly in ambulatory BP .