High-dose methylphenidate treatment of attention deficit hyperactivity disorder in a preschooler.

Although attention deficit hyperactivity disorder is thought to be present in preschoolers, there are no clear guidelines for dosing stimulant medications in this population. This is a case of a 4-year-old boy who was given 108 mg/day extended-release methylphenidate (OROS) MPH) (6.1 mg/kg/day) by his caregiver with notable behavioral improvement. However, weight loss incurred due to the anorexic side effect of the medication led the clinician to decrease his dose to 72 mg/day OROS MPH (3.7 mg/kg/day). The case highlights that some young children with attention deficit hyperactivity disorder treated with MPH may require higher doses than would be predicted by weight-based dosing. An increased frequency of side effects associated with high doses of MPH necessitates that the clinician balance the positive behavioral response of the medication with adverse side effects in determining ideal dose.