Hypocarnitinemia in the handicapped individuals who receive a polypharmacy of antiepileptic drugs.

Decrease in the serum concentrations of total and free carnitine were found in patients who had received multiple doses of antiepileptic drugs, either including or excluding sodium valproate. These concentrations were more depressed in a former patient group. In all patients there were no abnormal losses of carnitine in urine. Several factors which may be relevant to the hypocarnitinemia were surveyed statistically. The univariate correlation analyses revealed that in all the patients the total and the free carnitine levels were each correlated with the values of arm muscle circumference, and they were inversely correlated with the dosages of sodium valproate. Double regression analyses again revealed that the value of arm muscle circumference is the most critical positive factor, and dosage of sodium valproate is the most critical negative contributor, to both the total and the free serum carnitine concentrations. There was, however, some additional negative contribution by the dosage of phenytoin to the total carnitine concentration. These results indicate that although sodium valproate itself reduces the carnitine concentrations in serum, a poor muscle volume and co-administration of phenytoin with sodium valproate enhance hypocarnitinemia.