l-Carnitine occurs naturally as an essential cofactor of
fatty acid metabolism which is synthesised endogenously or obtained from dietary sources. In patients with primary
carnitine deficiencies, which may be life-threatening, and some secondary deficiencies such as organic acidurias, the exogenously administered compound is clearly beneficial: by abolishing
hypotonia, motor skills are improved, as are
muscle weakness and wasting. In preliminary clinical trials in patients with ischaemic
cardiac disease,
therapy with
l-carnitine has shown beneficial effects on myocardial function and metabolism and has improved exercise tolerance in patients with
angina pectoris-findings which require further substantiation in larger controlled studies. Moreover, while some interesting evidence suggests that
l-carnitine may find potential use in such diverse conditions as
carnitine deficiencies secondary to prolonged
total parenteral nutrition supplementation or chronic haemodialysis, hyperlipidaemias and the prevention of toxicity induced by
anthracyclines and
valproate, such findings must be regarded as preliminary. Exogenously administered
l-carnitine is very well tolerated. Thus, while its role in primary deficiencies is established, with its profile of negligible toxicity
l-carnitine is worthy of further investigation to more clearly define its therapeutic applications in a variety of conditions which may be indirectly related to alterations in
fatty acid metabolism.