Phenytoin Hypersensitivity Syndrome Associated with Glutathione S-Transferase, N-Acetyltransferase, Cytochrome P450 Polymorphisms

Observation: The anticonvulsant hypersensitivity syndrome is rare complication that occurs with the use of antiepileptic medications. All of the aromatic anticonvulsant drugs are metabolised by the cytochrome P-450 enzyme to a common arene oxide metabolite that is normally detoxified by epoxide hydrolase. A genetically determined inability to detoxify the toxic metabolites due to a defect in the enzyme epoxide hydrolase has been observed in patients with this hypersensitivity syndrome. We present a patient with severe phenytoin-induced hypersensitivity syndrome associated with glutathione S-transferase, N-acetyltransferase, and cytochrome P450 polymorphisms.