Differential time effect profiles of amlodipine, as compared to valsartan, revealed by ambulatory blood pressure monitoring, self blood pressure measurements and dose omission protocol

Amlodipine and valsartan are once-daily antihypertensive agents. To date, no comparison between these agents given as monotherapies was reported. This study was aimed to evaluate the therapeutic coverage and safety of amlodipine and valsartan in mild-to-moderate hypertensive patients. Multicenter, double-blind, randomized, comparative study. After a 4-week placebo wash-out period, 246 outpatients with office diastolic blood pressure 95 < or = DBP < or =110 mmHg and systolic blood pressure (SBP) < 180 mmHg, in addition to a mean daytime SBP and/or DBP > 135/85 mmHg on 24-h ambulatory blood pressure monitoring (ABPM), were randomly allocated to once-daily amlodipine 5-10 mg or valsartan 40-80 mg, for 12 weeks. In a subgroup of patients, 48-h ABPM were performed at the end of the treatment period. Dose omission was simulated by a single-blind placebo dosing. The primary efficacy end-point was the 24-h trough office BP after 12 weeks of active therapy. The reductions in 24-h trough BP were more pronounced in amlodipine compared with valsartan group as well in office [SBP: -17.8 +/- 10.9 vs. -14.6 +/- 11.2, P = 0.025, DBP: -12.7 +/- 7.2 vs. -10.9 +/- 7.8 mmHg, P = 0.06) as in ambulatory BP (SBP/DBP: -13.0 +/- 13.7/-10.8 +/- 9.1 vs. -7.2 +/- 19.4/-4.9 +/- 13.4 mmHg, P < 0.05). Forty-eight hours after the last active dose, the slope of the morning BP surge (4-9 h) was less steep with amlodipine vs. valsartan [DBP (P < 0.04), SBP (n.s.)]. Ankle edema were more often reported in amlodipine group. These results suggest a superior BP lowering and a longer duration of action with amlodipine compared with valsartan.