Carnitine deficiency associated with anticonvulsant therapy.

Valproic acid therapy is known to be associated with carnitine deficiency in adult as well as young epileptic patients. In a study of the possible existence of such side-effects with other anticonvulsants, 76.5% of adult patients treated with valproate were deficient in serum free carnitine, with acylcarnitine levels significantly higher than in controls (p less than 0.01), while the carnitine deficiency rate in a group of patients treated with anticonvulsants other than valproate was 21.5%. Since in clinical practice only about one fifth of patients are treated with valproate, this means that about 15% of epileptics are carnitine deficient because of valproate treatment and 17% because of other anticonvulsants. The mechanisms and clinical and biological consequences of the carnitine deficiency associated with antiepileptic drugs other than valproate are not known.

Determination of L-carnitine in serum, and implementation on the ABA-100 and CentrifiChem 600.

Deproteinization of serum samples by heating to 100 degrees C, then freezing, allows up to 60% of the volume of the sample to be recovered. Concentrations of L-carnitine in samples so treated are comparable with those obtained by more sophisticated and expensive methods, and precision and accuracy are similar to those of other available techniques. There is no medically significant difference between results obtained in the ABA-100 and CentrifiChem 600, and the method is suitable for screening studies. Concentrations in the serum of presumably healthy adults ranged from 29.3 to 66.1 mumol/L. As little as 3 mumol of L-carnitine per liter can be determined.