ASYMPTOMATIC HYPERAMMONEMIA IN CHILDREN TREATED WITH VALPROIC ACID

It is known that valproic acid changes the ammonia metabolism. It has been suggested that blood ammonia levels do not correlate with valproa te-induced encephalopathy.(1,2) In addition, the hyperammonemia togeth er with encephalopathy was reported both with hepatic dysfunction and without it.(3-5). It was also reported that therapy with valproic acid led to the decreased plasma free carnitine concentration associated w ith hyperammonemia.(6,7) Ohtani et al(8) reported that there was a neg ative correlation between plasma ammonia and carnitine levels in patie nts taking valproic acid, and after giving L-carnitine (50 mg/kg/day) for 4 weeks, both hyperammonemia and carnitine deficiency were improve d. We planned this study in patients without hepatic dysfunction and t aking valproic acid to evaluate: (1) whether or not hyperammonemia ris es; (2) if it is symptomatic; (3) if it rises, to what extent; (4) whi ch variables affect it; and (5) if it is responsive to oral L-carnitin e, and if so, how long carnitine therapy should be given to these pati ents.