Valproic acid induced pancreatitis: 16 new cases and literature overview

Valproic acid (VPA) is a commonly prescribed medication for generalized and focal epilepsy, migraine, neuropathic pain and bipolar disorder. The common side effects associated with VPA are typically benign, less common but more serious adverse effects may occur. These include hepatotoxicity, hyperammonemic encephalopathy, coagulation disorders and pancreatitis. Since 1979, a few cases of pancreatitis induced by VPA have been published in the medical literature. Method: We mailed a questionnaire to all members of the “German Section of the International League against Epilepsy“, containing questions about VPA-induced side effects. We also reviewed the medical literature for VPA-induced pancreatitis. Clinical characteristics and outcomes of these patients are summarized. Additionally a PubMed research for all published cases of VPA-induced pancreatitis was made and summarized. Results: 53 publications (90 patients) were found from 1979 to 2005. We received 450 answers to our survey, 254 of the physicians never noticed any side effects of VPA (56.4%), but, to our surprise 44 cases (16 of them with detailed information) of pancreatitis were reported only in Germany from 1994–2003. Non of these patients had been published previously. Conclusion: The difference between 90 patients reported worldwide from 1979 to 2005 and 44 documented cases only in Germany could show an underrated incidence of this severe side effect. Additionally, the outcome seemed to be better in our patients then in the published cases, only one of our patients died, 97.7% recovered completely. At present, increased consciousness of the risk of an VPA-induced pancreatitis and its presentation with acute abdominal pain, nausea, vomiting or flulike illness should be prompt the physicians to check for pancreatitis and discontinue the drug.