Background: Methylphenidate is a piperidine derivative stimulant drug. It inhibits the reuptake of dopamine and norepinephrine and improves the primary symptoms of Attention-Deficit/Hyperactivity Disorder. Methylphenidate may cause dyskinesias in children with Attention-Deficit/Hyperactivity Disorder, and concomitant irregularity in Electroencephalography may increase the likelihood of the neuropsychiatric side effects.
Case Report: A case of a 6.5-years-old boy who was admitted to the emergency room with unintended and uncontrolled behaviours after the first dose of this drug was presented. He was diagnosed with acute dyskinesia in the orofacial region and extremities, and then he was cured with biperiden lactate infusion in eighteen hours. Focal biphasic waves at right temporoparietal areas were recorded on his sleep-Electroencephalography.
Conclusion: In our case with both attention-deficit/hyperactivity disorder and epileptiform activity, dyskinesia occurrence after one single dose of 20 mg methylphenidate was discussed with the results of previous studies.