A prospective open trial of guanfacine in children with pervasive developmental disorders.

A common complaint for children with pervasive developmental disorder (PDD) is hyperactivity. The purpose of this pilot study was to gather preliminary information on the efficacy of guanfacine in children with PDD and hyperactivity. Children with PDD accompanied by hyperactivity entered the open-label trial if there was a recent history of failed treatment with methylphenidate or the child did not improve on methylphenidate in a multisite, placebo-controlled trial. Children (23 boys and 2 girls) with a mean age of 9.03 (+/-3.14) years entered the open-label trial. After 8 weeks of treatment, the parent-rated Hyperactivity subscale of the Aberrant Behavior Checklist (ABC) went from a mean of 31.3 (+/-8.89) at baseline to 18.9 (+/-10.37) (effect size = 1.4; p < 0.001). The teacher-rated Hyperactivity subscale decreased from a mean of 29.9 (+/-9.12) at baseline to 22.3 (+/-9.44) (effect size = 0.83; p < 0.01). Twelve children (48%) were rated as Much Improved or Very Much Improved on the Clinical Global Impressions- Improvement. Doses ranged from 1.0 to 3.0 mg/day in two or three divided doses. Common adverse effects included irritability, sedation, sleep disturbance (insomnia or midsleep awakening), and constipation. Irritability led to discontinuation in 3 subjects. There were no significant changes in pulse, blood pressure, or electrocardiogram. Guanfacine may be useful for the treatment of hyperactivity in children with PDD. Placebo-controlled studies are needed to guide clinical practice.