Objective:To investigate the ambulatory blood pressure (BP) lowering efficacy and tolerability of initial high versus low lose of amlodipine in patients with mild or moderate hypertension.Methods:Eligible patients with mild or moderate hypertension (clinic systolic/diastolic BP, 140-159/90-99 mmHg) were randomly allocated 8-week treatment of levoamlodipine 2.5 mg/day (n=351) or 5.0 mg/day (n=350),respectively.This analysis included the patients (n=268 and n=263, respectively) who had valid ambulatory BP recordings both at baseline and 8 weeks of follow-up.