Efficacy and safety of low-dose antihypertensive combination of amlodipine, telmisartan, and chlorthalidone: A randomized, double-blind, parallel, phase II trial. The aim of this clinical trial was to assess the efficacy and safety of low-dose triple combinations of amlodipine, telmisartan, and chlorthalidone in patients with essential hypertension. After a 2-week placebo run-in period, 176 patients were randomized to seven treatment groups (placebo, quarter-dose combination, third-dose combination, half-dose combination, amlodipine 5 mg, amlodipine 10 mg, and telmisartan 80 mg) and administered the assigned study drug orally for 8 weeks. The primary efficacy endpoint was the change in the mean sitting systolic blood pressure (BP) (MSSBP) at Week 8. The MSSBP and mean sitting diastolic BP