L-carnitine kinetics in chronic hemodialysis patients: comparison between oral and intravenous supplementation

Introduction: In order to clarify the characteristics of different administration routes and to optimize the dosage, carnitine kinetics was investigated under oral and intravenous supplementation. Methods: L- carnitine was administered orally (900mg) for 12months, intravenously (1000 mg) for 3months and (500mg) for 3months sequentially in 18 chronic hemodialysis patients. Plasma free and acyl carnitine concentrations were assessed before and after hemodialysis procedure at the end of each administration protocol. The muscle carnitine content was calculated by active transport curve. Results: Plasma free carnitine concentration increased from 22.1±6.9 μM/L to 139.1±40.4 μM/L (900 mg p.o), 280.1±52.2μM/L (1000 mg i.v) and 169.7±25.9 μM/L (500mg i.v) before dialysis procedure. Although acyl/free carnitine ratio decreased significantly after each supplementation method (p<0.05), there was no difference of acyl/free carnitine ratio among each group. The simulation of muscle carnitine content indicated that the active transport is mainly depend on high affinity component, and oral 900mg daily supplementation and intravenous 500 mg administration after each hemodialysis procedure are enough dosage to achieve the normal carnitine content of muscle tissue in chronic hemodialysis patients. Conclusion: It would be suggested that oral 900 mg daily supplementation and intravenous 500 mg administration (10 mg/kg) after each hemodialysis procedure are reasonable dosage and have equal efficacy from the viewpoint of muscle carnitine content, although the plasma carnitine concentration curves were quite different.