Blood Pressure Control with a Single-Pill Combination of Indapamide Sustained-Release and Amlodipine in Patients with Hypertension: The EFFICIENT Study

OBJECTIVE: Despite antihypertensive treatment, most hypertensive patients still have high blood pressure (BP), notably high systolic blood pressure (SBP). The EFFICIENT study examines the efficacy and acceptability of a single-pill combination of sustained-release (SR) indapamide, a thiazide-like diuretic, and amlodipine, a calcium channel blocker (CCB), in the management of hypertension. METHODS: Patients who were previously uncontrolled on CCB monotherapy (BP≥140/90 mm Hg) or were previously untreated with grade 2 or 3 essential hypertension (BP≥160/100 mm Hg) received a single-pill combination tablet containing indapamide SR 1.5 mg and amlodipine 5 mg daily for 45 days, in this multicenter prospective phase 4 study. The primary outcome was mean change in BP from baseline; percentage of patients achieving BP control (BP<140/90 mm Hg) was a secondary endpoint. SBP reduction (ΔSBP) versus diastolic BP reduction (ΔDBP) was evaluated (ΔSBP/ΔDBP) from baseline to day 45. Safety and tolerability were also assessed. RESULTS: Mean baseline BP of 196 patients (mean age 52.3 years) was 160.2/97.9 mm Hg. After 45 days, mean SBP decreased by 28.5 mm Hg (95% CI, 26.4 to 30.6), while diastolic BP decreased by 15.6 mm Hg (95% CI, 14.5 to 16.7). BP control (<140/90 mm Hg) was achieved in 85% patients. ΔSBP/ΔDBP was 1.82 in the overall population. Few patients (n = 3 [2%]) reported side effects, and most (n = 194 [99%]) adhered to treatment. CONCLUSION: In patients who were previously uncontrolled on CCB monotherapy or untreated with grade 2 or 3 hypertension, single-pill combination indapamide SR/amlodipine reduced BP effectively—especially SBP— over 45 days, and was safe and well tolerated. TRIAL REGISTRATION: Clinical Trial Registry – India CTRI/2010/091/000114