Objective: Short-term, controlled studies of extended-release guanfacine (GXR), a selective alpha(2A)-adrenoreceptor agonist, demonstrate efficacy in treating attention-deficit/hyperactivity disorder (ADHD) symptoms as monotherapy. This 2-year open-label study was conducted to further assess the long-term safety and efficacy of GXR.
Methods: Study participants, aged 6-17 years with ADHD, had previously been exposed to GXR therapy alone or in combination with psychostimulants in one of two antecedent trials. In this study, doses were titrated to 1, 2, 3, or 4 mg/day of GXR alone or in combination with a psychostimulant. Safety and efficacy data collected at clinic visits over 24 months provided further evidence of the overall safety and efficacy of GXR for treating ADHD.
Results: The majority of adverse events (AEs) were mild to moderate, and few patients discontinued the study because of an AE. Efficacy measures demonstrated significant improvement beginning in the first month and lasting through the end of the 24-month treatment period. Throughout the entire 2-year study, 202 subjects (77.1%) discontinued and 60 (22.9%) completed the study.
Conclusions: Overall, these data support that GXR monotherapy is generally safe and effective for treating ADHD.