Efficacy of guanfacine extended release assessed during the morning, afternoon, and evening using a modified Conners'...

The purpose of this study was to evaluate the efficacy of once-daily guanfacine extended release (GXR) monotherapy administered either in the morning or evening, using a modified Conners' Parent Rating Scale-Revised: Short Form (CPRS-R:S) assessed three times/day in children with attention-deficit/hyperactivity disorder (ADHD).

This multicenter, double-blind, placebo-controlled study randomized children 6-12 years of age with ADHD into three groups: GXR a.m. (GXR in the morning and placebo in the evening), GXR p.m. (placebo in the morning and GXR in the evening), or twice-daily placebo. The CPRS-R:S, administered in the morning, afternoon, and evening prior to each study visit, was a secondary measure of efficacy.

A total of 333 subjects were included in the analysis population (GXR a.m., n=107; GXR p.m., n=114; placebo, n=112). At visit 10, last observation carried forward (LOCF), subjects receiving GXR demonstrated significantly greater improvement from baseline in the daily mean CPRS-R:S total score, as well as in each of the morning, afternoon, and evening CPRS-R:S assessments, compared with placebo, regardless of the time of GXR administration (p<0.001 vs. placebo for GXR a.m. and GXR p.m.). In addition, subjects receiving GXR showed significantly greater improvements from baseline in each subscale score (oppositional, cognitive problems/inattention, hyperactivity, and ADHD index) compared with those receiving placebo, regardless of time of administration (p<0.003 vs. placebo across all subscales for GXR a.m. and GXR p.m.).

These results provide further support for the demonstrated efficacy of once-daily GXR in reducing ADHD symptoms, and demonstrate that response is consistent throughout the day regardless of the time of administration, with improvement seen in ratings of oppositional as well as of ADHD symptoms.