Dyskinesia induced by phenytoin

Abstract

-Phenytoin is an effective antiepileptic drug, although, it can be associated with many side effects, including dyskinesia. Objective: To describe the clinical characteristics of phenytoin induced dyskinesia. Methods: We investigated the occurrence of involuntary movements in patients followed at our adult and pediatric epilepsy clinics during the period of one year. Results: Three patients presented with phenytoin-induced dyskinesia: one adult with axial and orofacial dyskinesia, and two children with choreoathetosis. They did not have other signs of phenytoin intoxication and had complete recovery after phenytoin withdrawal. Conclusion: Phenytoin induced dyskinesia may occur during either chronic or initial treatment and with normal serum phenytoin levels. However, it occurs most often in patients on polytherapy, usually after increasing dosage and with toxic serum levels. Other signs of phenytoin intoxication may be present in these patients, but often the dyskinesia is the only side effect, which may delay the diagnosis and treatment. The clinical characteristics of the involuntary movements vary and may be focal or generalized, most often characterized by choreoathetosis and dyskinesias. These may last for hours, days or even years, but frequently disappear completely after phenytoin withdrawal. KEY WORDS: phenytoin, dyskinesia, involuntary movementDiscinesia induzida por fenitoína.RESUMO -Fenitoína é droga anti-epiléptica eficaz, mas pode estar associada a vários efeitos colaterais, inclusive discinesia. Objetivo: Descrever as características clínicas da discinesia induzida por fenitoína. Método: Avaliamos a ocorrência de movimentos involuntários em pacientes seguidos nos ambulatórios de epilepsia durante o período de um ano. Resultados: Três pacientes apresentaram discinesia induzida por fenitoína: um adulto com discinesia orofacial e duas crianças com coreoatetose. Eles não tinham outros sinais de intoxicação por fenitoína e apresentaram recuperação completa após a retirada da fenitoína. Conclusão: Discinesia induzida pela fenitoína pode ocorrer durante tratamento crônico ou no início do tratamento e com níveis séricos normais de fenitoína. Entretanto, na maioria das vezes ocorre em politerapia e geralmente após aumento da dose e com níveis tóxicos de fenitoína. Outros sinais de intoxicação podem estar presentes, mas muitas vezes a discinesia é o único efeito adverso, o que pode atrasar o diagnóstico e tratamento. Os movimentos involuntários podem ser focais ou generalizados. Podem durar horas, dias ou até anos, mas freqüentemente desaparecem completamente após a retirada da fenitoína.PALAVRA-CHAVE: fenitoína, discinesia, movimento involuntário.Phenytoin is a widely used anticonvulsant, considered to be one of the first line drugs for partial seizures as well as for most forms of generalized seizures 1 . Despite its complex and unpredictable pharmacokinetic properties, phenytoin is usually safe, efficient, inexpensive and relatively easy to use. However, the use of this major anticonvulsant is l...

Familial Temporal Lobe Epilepsy as a Presenting Feature of Choreoacanthocytosis

“…Medical management of epilepsy in ChAc patients is complicated by the fact that the comorbid involuntary movements may be worsened by some of the AEDs. AEDs are known to have a potential influence on involuntary movements in patients with underlying movement disorders (21–25). This was found with CBZ and LTG for patient 1 and with LTG for patient 2.…”

Phenytoin-Induced Choreoathetosis in Patients with Severe Myoclonic Epilepsy in Infancy

“…Choreoathetosis is a relatively rare complication of phenytoin (PHT) therapy. According to reported cases, such PHT-induced movement disorders tend to occur in epileptic patients during childhood or young adulthood, especially in association with preceding organic brain damage and polypharmacy [14,19].…”

Orolingual Dyskinesia and Involuntary Neck Movements Caused by Phenytoin Intoxication

“…[1][2][3] Montenegro et al identified one patient with axial and orofacial dyskinesia and two patients with choreoathetosis in a 1-year period, and literature shows that the main findings in phenytoin-intoxicated dyskinesic patients were choreoathetosis, dystonia, orofacial dyskinesia, and ballism, in decreasing order. [1][2][3][4][5] Brain damage has been shown to cause sensitization to the toxic effects of phenytoin. 2 The exact pathophysiology of the occurrence of involuntary movement in phenytoin intoxication is still obscure; however, the most likely mechanism seems to be a dopaminergic, cholinergic, and serotonergic imbalance within the basal ganglia system in these patients.…”