Phenytoin-induced orofacial dyskinesia. A case report

A 56-year-old man with a small glioblastoma multiforme in the right parasagittal region developed orofacial dyskinesia and slight writhing movement of his hands during treatment with phenytoin and phenobarbitone. The serum concentration of phenytoin was within the therapeutic range. The involuntary movements subsided following the withdrawal of the drugs. Phenytoin-induced involuntary movements have not been described previously in a case with such a small parasaggital tumour treated with phenytoin at a serum concentration of therapeutic range.