Phenytoin Toxicity: A Case Report

Background: Phenytoin is a commonly used sedative antiepileptic medication in many countries. It is used against tonic-clonic and complex partial seizures. Phenytoin is reported to cause a range of deleterious and erratic side effects at therapeutic and toxic doses. Case report: An eighteen year old female presented with ataxia, nystagmus, gingival hypertrophy, nodular skin lesions and hirsutism while she was on treatment with oral phenytoin at 200 mg once daily since the past five years for seizures. Based on the presenting signs and symptoms, her condition was diagnosed as phenytoin induced toxicity. The symptoms improved significantly after the offending drug was withdrawn. Alternatively she was started on oral carbamazepine. Naranjo and WHO causality assessment was done, indicating a probable relationship between the patient's symptoms and her use of phenytoin. Conclusion: This case report and review highlights the adverse drug reactions of phenytoin and the need of regular monitoring in patients on long term therapy.