A Case Series of Severe Hyperammonemia Encephalopathy Related to Valproate: Can Antipsychotics Increase the Risk?

  • Effat Davoudi-Monfared
  • Mojan Radmehr Department of Clinical Pharmacy, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran.
  • Padideh Ghaeli Roozbeh Psychiatric hospital, Tehran university of medical sciences, Iran
  • Maryam Mousavi
Keywords: Antipsychotic; Encephalopathy; Hyperammonemia; Valproate Derivatives


Valproate-induced hyperammonemia is a common side effect of valproate, which may occur either without any symptoms or may rarely cause symptoms of encephalopathy. Different risk factors have been defined for this side effect, including some nutritional deficiencies and polypharmacy (eg, other anticonvulsants). Three cases with psychiatric disorder who showed symptoms of severe hyperammonemia encephalopathy and had taken valproate with antipsychotics, especially risperidone, are presented here. In all cases, the symptoms were improved by discontinuation of valproate. Administration of antipsychotic may be considered as a risk factor for hyperammonemic encephalopathy related to valproate, specifically in some prone populations.


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How to Cite
Davoudi-Monfared E, Radmehr M, Ghaeli P, Mousavi M. A Case Series of Severe Hyperammonemia Encephalopathy Related to Valproate: Can Antipsychotics Increase the Risk?. Iran J Psychiatry. 14(3):248-252.
Case Report(s)