Multicenter trial of L-carnitine in maintenance hemodialysis patients. I. Carnitine concentrations and lipid effects

Previous studies have reported conflicting results of carnitine supplementation on plasma lipids in patients with chronic renal failure. We therefore performed a four center, double-blind placebo controlled trial to evaluate the effects of post-hemodialysis intravenous injection of L-carnitine in ESRD patients on maintenance hemodialysis. Thirty-eight patients received up to six months of L-carnitine infusions (20 mg/kg) post-dialysis and 44 patients received placebo infusions. In both groups of patients, baseline pre-dialysis plasma and red blood cell total carnitine levels were normal, but pre-dialysis plasma-free carnitine concentrations and free/total ratios were subnormal, and plasma acyl levels were elevated. Post-dialysis plasma free and total carnitine concentrations were also subnormal. Plasma and red blood cell total carnitine levels rose eightfold in carnitine recipients, but were unchanged from baseline in those receiving placebo. There were no significant changes observed in plasma triglycerides, HDL-cholesterol or other lipoprotein parameters in either the carnitine or placebo treated groups. We conclude that carnitine metabolism is altered in uremia. Furthermore, in a randomly-selected hemodialysis population, L-carnitine injection at the dose of 20 mg/kg results in significant increases in blood (and perhaps tissue) carnitine levels, but this is not associated with any major effects on lipid profiles.