title: Evaluation of electrocardiographic and hemodynamic effects of caffeine with acute dosing in healthy volunteers.
abstract: OBJECTIVE
  To evaluate the effects of moderate, single-dose caffeine consumption on electrocardiographic variables: PR, QRS, QT, QTc, and RR intervals, and QT and QTc interval dispersion. Effects of caffeine on blood pressure and heart rate also were evaluated.
  
  
  METHODS
  Randomized, double-blind, placebo-controlled, crossover study.
  
  
  METHODS
  University school of pharmacy.
  
  
  METHODS
  Ten healthy volunteers aged 17 years or older.
  
  
  METHODS
  Participants abstained from caffeinated products for at least 2 days before the study began and were randomly designated to receive placebo or caffeine 400 mg on various days. For each of the study phases, a baseline 12-lead electrocardiogram (ECG) was performed and a subsequent 12-lead ECG performed 3 hours after ingesting the study drug. Blood pressure readings were taken with each ECG.
  
  
  RESULTS
  No significant changes in any intragroup or intergroup electrocardiographic variables occurred. Caffeine increased blood pressure (systolic blood pressure [SBP]/diastolic blood pressure [DBP]) from 118+/-5/75+/-6 mm Hg to 128+/-8/77+/-7 mm Hg versus baseline (p=0.0022 and p=0.0368 for SBP and DBP, respectively). After drug dosing, SBP in the caffeine group was significantly higher than in the placebo group (128+/-8 mm Hg versus 119+/-7 mm Hg, p=0.0174).
  
  
  CONCLUSIONS
  Moderate caffeine consumption by healthy young adults does not acutely affect PR, QRS, QT, QTc, and RR intervals, or QT and QTc interval dispersion. Caffeine-naive subjects experienced persistent elevations in SBP and DBP 3 hours after caffeine ingestion, indicating that longer caffeine abstinence than that which is recommended is necessary for blood pressure determination in the clinical setting.
authors: University of Connecticut School of Pharmacy, Storrs, USA.
authors: R
authors: R
authors: Ammar
authors: J C
authors: JC
authors: Song
authors: J
authors: J
authors: Kluger
authors: C M
authors: CM
authors: White
mesh_terms: D000284:Administration, Oral; D000328:Adult; D002110:Caffeine / Q000493:pharmacokinetics / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000493:pharmacokinetics / Q000494:pharmacology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006207:Half-Life; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D008297:Male
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine