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Guanfacine XR does not affect daytime sleepiness, increases evening sleepiness in children, adolescents with ADHD, safety analysis shows

Friday, October 26 2007 | Comments
Evidence Grade 0 What's This?
Phase II data confirm the safety profile of guanfacine extended release (XR) in children and adolescents with attention-deficit/hyperactivity disorder and suggest that the drug may increase evening sleepiness in these patients, but it does not increase daytime sleepiness in the classroom.

The current analysis was conducted to assess the safety and daytime sleepiness effects of guanfacine XR, which has been associated with sedation in previous studies, in 178 children aged 6 to 17 years who participated in a double-blind, analog classroom, dose-optimization study. The children were randomized to receive guanfacine XR (n=121) or placebo (n=57) for 6.5 weeks, during which time an optimal dose was established and maintained. Of these children, 166 completed >=6 weeks of treatment.

The starting dose of guanfacine XR was 1 mg/day; this dose could be increased (or reduced) in 1 mg/week intervals to a maximum of 3 mg/d. Ultimately, 14 of the children received guanfacine XR 1 mg/d, 37 received the 2 mg/d dose, and 70 received the 3 mg/d dose.

Responses to the Pediatric Daytime Sleepiness Scale (PDSS) showed no evidence of increased daytime sleepiness with guanfacine XR relative to placebo. In fact, the authors noted, small decreases in PDSS scores were observed in the guanfacine XR group (but not in the placebo group) toward the end of the treatment period (P<=.05 vs baseline), possibly suggesting reduced daytime sleepiness and increased alertness with active treatment.

Similarly, responses to the Pictorial Sleepiness Scale (PSS; a modified visual analog scale used to assess daytime and evening sleepiness) showed no significant effect of guanfacine XR on daytime sleepiness. However, PSS data collected at 10 hours and 12 hours postdose showed increased evening sleepiness with guanfacine XR relative to placebo.

Treatment-emergent adverse events occurred in 79.3% of the guanfacine XR group and 70.2% of the placebo group.

Relative to placebo, guanfacine XR was associated with a higher incidence of somnolence (22.8% vs 41.3%), sedation (5.3% vs 7.4%), and fatigue (0.0% vs 5.0%).

Treatment-emergent adverse events considered possibly or probably related to treatment were reported by 62.0% of the guanfacine XR group and 43.9% of the placebo group; most were mild to moderate in severity, according to the study authors. The most common of these events were somnolence (40.5% vs 22.8%) and headache (14.9% vs 3.5%).

The researchers also observed small decreases in blood pressure and pulse rate, which they noted were consistent with the known effects of the drug. In addition, they reported a dose-dependent decrease in heart rate that was similar to the decrease in pulse rate. (Kollins SH, et al. Poster B48.)

This information concerns a use that has not been approved by the Food and Drug Administration.

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