Hyperammonemia Induced by Interaction of Valproate and Quetiapine

Athar      Halaby; Ramzi      Haddad; Wadih   J.   Naja

Abstract

Introduction: Hyperammonemia is one of the rare nevertheless serious side effects associated with valproic acid treatment. Two cases of valproic acid induced hyperammonemia are detailed in this article.

Cases: Case one describes an adult male who developed hyperammonemia after acute exposure to valproic acid as a treatment for his bipolar disorder-manic episode. Case two developed a similar pattern of toxicity but after chronic exposure to valproic acid. Both patients were receiving a combination of valproic acid and quetiapine.

Discussion: Measurement of the ammonium level should be considered where there is a decreased level of consciousness in patients receiving valproic acid irrespective of the diagnosis and even after a long term exposure. A possible risk of hyperammonemia can result from a combination of valproic acid and quetiapine, however further studies are yet needed to confirm this hypothesis.

Keywords: Hyperammonemia, quetiapine, valproic acid.

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