title: Effective dosing of L-carnitine in the secondary prevention of cardiovascular disease: a systematic review and meta-analysis.
abstract: BACKGROUND
  L-carnitine supplementation has been associated with a significant reduction in all-cause mortality, ventricular arrhythmia, and angina in the setting of acute myocardial infarction (MI). However, on account of strict homeostatic regulation of plasma L-carnitine concentrations, higher doses of L-carnitine supplementation may not provide additional therapeutic benefits. This study aims to evaluate the effects of various oral maintenance dosages of L-carnitine on all-cause mortality and cardiovascular morbidities in the setting of acute MI.
  
  
  METHODS
  After a systematic review of several major electronic databases (PubMed, EMBASE, and the Cochrane Library) up to November 2013, a meta-analysis of five controlled trials (n = 3108) was conducted to determine the effects of L-carnitine on all-cause mortality and cardiovascular morbidities in the setting of acute MI.
  
  
  RESULTS
  The interaction test yielded no significant differences between the effects of the four daily oral maintenance dosages of L-carnitine (i.e., 2 g, 3 g, 4 g, and 6 g) on all-cause mortality (risk ratio [RR] = 0.77, 95% CI [0.57-1.03], P = 0.08) with a statistically insignificant trend favoring the 3 g dose (RR = 0.48) over the lower 2 g dose (RR = 0.62), which was favored over the higher 4 g and 6 g doses (RR = 0.78, 0.78). There was no significant differences between the effects of the daily oral maintenance dosages of 2 g and 6 g on heart failure (RR = 0.53, 95% CI [0.25-1.13], P = 0.10), unstable angina (RR = 0.90, 95% CI [0.51-1.58], P = 0.71), or myocardial reinfarction (RR = 0.74, 95% CI [0.30-1.80], P = 0.50).
  
  
  CONCLUSIONS
  There appears to be no significant marginal benefit in terms of all-cause mortality, heart failure, unstable angina, or myocardial reinfarction in the setting of acute MI for oral L-carnitine maintenance doses of greater or less than 3 g per day.
authors.affiliation: Department of Cardiology, Daqing General Hospital Group, Oilfield General Hospital, No, 9 Zhongkang Road, Daqing City 163001, Heilong Jiang Province, China. srp0459@163.com.
authors.forename: Ruiping
authors.initials: R
authors.lastname: Shang
authors.forename: Zhiqi
authors.initials: Z
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Li
mesh_terms: D000284:Administration, Oral; D002317:Cardiovascular Agents / Q000008:administration & dosage*; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000401:mortality / Q000517:prevention & control*; D002331:Carnitine / Q000008:administration & dosage*; D016009:Chi-Square Distribution; D004334:Drug Administration Schedule; D054796:Drug Dosage Calculations; D006801:Humans; D016017:Odds Ratio; D012008:Recurrence; D012307:Risk Factors; D055502:Secondary Prevention / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D002317:Cardiovascular Agents; D002331:Carnitine