title: Differential effects of morning or evening dosing of amlodipine on circadian blood pressure and heart rate.
abstract: OBJECTIVE
  To compare the effects of morning and evening dosing of amlodipine on both circadian blood pressure (BP) and heart rate (HR) in mild-to-moderate essential hypertension.
  
  
  METHODS
  A perspective, double-blind, randomized, crossover design with dose titration.
  
  
  METHODS
  Sixty-two patients recruited in the study were aged 21-77 years and had mild-to-moderate essential hypertension. At the end of a 2-week single-blind, placebo run-in period, eligible patients were randomly assigned to morning (7 AM) and evening (9 PM) amlodipine treatment. The initial dose was 5 mg. After 2 weeks of double-blind therapy, patients with a seated diastolic blood pressure > or =90 mm Hg had their doses titrated upward to 10 mg, while the other patients remained on their original 5 mg doses for another 4 weeks period, than crossover to the alternate dosing regimen for 6 additional weeks. The 24-h ambulatory monitoring was performed at baseline and at 6 and 12 weeks after randomization.
  
  
  RESULTS
  24-h diastolic BP load (11.0 +/- 17.5% vs. 6.5 +/- 9.1%, P < 0.05) and night-time BP load (28.5 +/- 31.4%/17.7 +/- 28.2% vs. 20.0 +/- 27.9%/9.2 +/- 17.8%, P < 0.05/0.05) were significantly greater with evening dosing compared with morning dosing. Nocturnal fall of BP was greater with morning dosing than with evening dosing (9.8 +/- 6.7/7.4 +/- 5.3 vs. 6.7 +/- 6.6/5.4 +/- 5.4 mm Hg, P < 0.01/0.05). Percentage of nocturnal BP fall was greater with morning dosing versus with evening dosing (7.9 +/- 5.3%/9.6 +/- 6.8% vs. 5.4 +/- 7.0%/7.0 +/- 6.9%, P < 0.01/0.05).
  
  
  CONCLUSIONS
  Morning administered amlodipine had a better effect on the circadian BP compared with evening administrated amlodipine in mild-to-moderate essential hypertension.
authors: Department of Cardiology, The First Affiliated Hospital, Zhejiang University, College of Medicine, Hangzhou, P.R. China. qiuyuangang@yahoo.com.cn
authors: Yuan-Gang
authors: YG
authors: Qiu
authors: Jun-Zhu
authors: JZ
authors: Chen
authors: Jian-Hua
authors: JH
authors: Zhu
authors: Xue-Yan
authors: XY
authors: Yao
mesh_terms: D000328:Adult; D000368:Aged; D017311:Amlodipine / Q000008:administration & dosage / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects*; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use*; D002940:Circadian Rhythm; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D002121:Calcium Channel Blockers; D017311:Amlodipine