Methylphenidate-induced acute orofacial and extremity dyskinesia.

Methylphenidate is a short-acting stimulant. In this article, the authors report a 7-year-old male patient who presented with orofacial and limb dyskinesia after his first dose of methylphenidate treatment for a diagnosis of attention-deficit/hyperactivity disorder; he was also receiving sodium valproate treatment for epilepsy. Orofacial dyskinesia appeared 5 hours after methylphenidate administration, persisted for 10 hours, and had completely resolved within 2 days. Although limb dyskinesia after methylphenidate is a commonly reported side effect, to the authors' knowledge this is only the second reported case to develop both orofacial and limb dyskinesia in the acute period after the first dose of methylphenidate. This case is reported to emphasize the potential side effects of methylphenidate, individual differences in drug sensitivities, and drug-receptor interactions via different mechanisms.