Carnitine balance and effects of intravenous L-carnitine in two patients receiving long-term total parenteral nutrition.

Two patients requiring total parenteral nutrition for 34 and 39 months, had plasma and urinary carnitine assays and plasma lipid assays performed before and during intravenous administration of 400 mg (2500 mumol) of L-carnitine for 7 days, followed by 40 mg (240 mumol) daily continuously. One patient had generalized lethargy and weakness which resolved within the first 5 days of carnitine administration. The plasma-free carnitine levels in this patient rose significantly. The other patient was asymptomatic and while there was no significant change in the plasma-free carnitine levels during carnitine administration, this patient remained in positive carnitine balance throughout the study. There were no significant changes in plasma lipid levels in either patient. In adult patients requiring long-term total parenteral nutrition who are otherwise normal, intravenous L-carnitine may be required to supplement the patients endogenous carnitine production.