The effects of pemoline (Cylert) in 28 children with attention deficit disorder (ADD), 23 with and 5 without hyperactivity, were evaluated for dose-response, timing of response after ingestion, and duration of effect, in a double-blind, placebo-controlled, crossover study at the Child Development Clinic of the Department of Neurology, Hospital for Sick Children, Toronto, Canada. Using doses of 18.75, 37.5, 75, and 112.5 mg of pemoline, q.a.m., each dose administered at 9 am for 1 week, performance was measured by number of math problems completed correctly, teacher-recorded on-task behavior and noncompliance, and Abbreviated Conners Teacher Rating Scale. Tests were completed immediately and beginning 2, 4, and 6 hours after drug ingestion. Beneficial effects of pemoline on classroom behavior and academic performance were linear, beginning 2 hours after ingestion and lasting at least 7 hours. Side effects during observation were minimal, and response was comparable to that reported in studies of methylphenidate. 
COMMENT. The commonly held belief that response to pemoline is gradual and sometimes delayed for 3 or 4 weeks was contradicted by the results of this study that demonstrate an acute beneficial effect, comparable to that of methylphenidate. The authors recommend that doses of pemoline higher than 18.75 or 37.5 mg may be needed for optimal benefit, and a prolonged response may be expected after a single morning dose. The side-effect of insomnia, reported in 32% of patients in one previous long-term trial, could not be evaluated in the present study because parent and sleep evaluations were not included. In my own patients with a complaint of sleep disturbance during treatment with pemoline, the side-effect was reported soon after initiation of therapy, suggesting a more acute onset of response than that noted in the manufacturer’s reports. The present study confirms the need to consider increments of dosage more rapidly than recommended in the PDR.