Valproic acid-induced pancreatitis in childhood epilepsy: case series and review

In the past 6 years, 11 children on valproic acid have developed pancreatitis in our children's hospital. Valproic acid has been used as one of the primary anticonvulsants for generalized seizures in children for the past 25 years. A literature review reveals mostly singular reports of pancreatitis over the past decade. The charts of the 11 patients with valproic acid-induced pancreatitis were reviewed. Dosage, valproic acid serum levels, duration of therapy, and concomitant medications were examined. Families were contacted by telephone to determine the formulation (brand name vs generic) of valproic acid at the time of diagnosis. Six girls and five boys were studied. The ages ranged from 4 to 16 years. Eight of 11 children presented with an acute abdomen. Unexpectedly, three children presented with a flulike illness. Serum lipase values ranged from 341 to 5576 U/L (normal range < 190 U/L). The dose of valproic acid ranged from 20 to 50 mg/kg. Serum levels ranged from 334 to 884 micromol/L (therapeutic range 350-800 micromol/L). Six of the patients were on monotherapy. Seven children were on brand-name drugs. Four of the children had an abnormal neurologic syndromic diagnosis (West syndrome, Rett syndrome, Lowe syndrome, and Angelman's syndrome). Six of the children had a history of drug allergies with a skin rash. Valproic acid was reintroduced in one child and resulted in a second episode of pancreatitis. Resolution of symptoms usually took several weeks following discontinuation of the drug. No association was found with valproic acid dosage, type of preparation, serum levels, duration of therapy, or presence of concomitant medications. Pancreatitis is a severe adverse effect of valproic acid use in children. Dose, duration of treatment, serum valproic acid levels, generic preparation, and the presence of concomitant antiepileptic drugs do not appear to be risk factors. Children with known drug sensitivity might be at risk. Lipase levels at the time of an acute abdomen or a flulike illness in epileptic children taking valproic acid can reveal early stages of pancreatitis and are recommended.