• We observed two patients who developed coma following administration of valproate in dosages of 32 to 40 mg/kg per day. Valproate levels were within the therapeutic range, and results of liver function studies were normal. Both patients had ketosis and adipic aciduria. Plasma free carnitine levels were decreased during coma and after recovery. One patient excreted ethylmalonic acid, butyrylcarnitine, and glutarylcarnitine during and after resolution of coma, suggesting a multiple acyl coenzyme A dehydrogenation defect. Low serum carnitine levels may predispose patients to development of altered consciousness when treated with valproate.
Triggs WJ, Bohan TP, Lin S, Willmore LJ. Valproate-Induced Coma With Ketosis and Carnitine Insufficiency. Arch Neurol. 1990;47(10):1131–1133. doi:10.1001/archneur.1990.00530100101021