United States of America - A letter has been issued to health care professionals by the manufacturer of levocarnitine (Carnitor®), to emphasize that only IV preparations of this drug are approved for use in patients with end-stage renal disease. The labelling changes have been made to the Precautions section as a result of reports being received by the company where oral levocarnitine was administered to patients with end-stage renal disease. The changes outline the following points.

• Patients with severe renal impairment or end - stage renal disease should not be administered long-term, high-dosage levocarnitine due to accumulation of major metabolites, specifically trimethylamine and trimethylamine-N-oxide, which cannot undergo efficient renal clearance.

• The formation of these metabolites does not occur to the same extent when levocarnitine is administered intravenously.

• Increased trimethylamine concentrations have been associated with possible neurophysiological effects and a ‘fishy’ body odour. The manufacturer lists nausea, vomiting, body odour, gastritis and seizures as adverse events that have been reported with levocarnitine.

Reference: Information from Sigma Tau, 13 July 2001. Communicated on http://www.fda.gov