Plasma and red blood cell carnitine and carnitine esters during L-carnitine therapy in hemodialysis patients.

Plasma and red blood cell (RBC) carnitine and acylcarnitines were determined in 20 hemodialysis (HD) patients during three different L-carnitine dosages (1, 5, and 15 mg/kg body wt), each for 3 mo. Before L-carnitine treatment, free carnitine was significantly lowered in plasma but elevated in RBCs compared with healthy subjects. Short-chain acylcarnitines were elevated in plasma and normal in RBCs. HD therapy decreased plasma free and acylcarnitines markedly but did not influence RBC values. Low-dose L-carnitine treatment normalized both plasma- and RBC-free carnitine. Dosages of 5 and 15 mg/kg body wt increased plasma and intracellular carnitine and carnitine esters impressively. Plasma and RBC carnitine fractions remained elevated even after a 6-wk washout period. Low-dose L-carnitine treatment is sufficient to correct disturbed plasma and RBC carnitine and carnitine esters of HD patients. Elevated RBC carnitine esters decreased very slowly, suggesting low RBC carnitine turnover. Carnitine overdosage should be prevented in those patients who benefit from carnitine therapy.