Children diagnosed with Attention Deficit Hyperactivity Disorder who respond inadequately to psychostimulants alone would benefit from combination therapy with a high blood pressure drug in controlling their actions and improving focus, according to a study.

Extended release tablets of high blood pressure drug Guanfacine can be used in combination with other medications. A study found that the drug is both safe and effective when used in conjunction with psychostimulants in children and adolescents with ADHD who had suboptimal responses to a psychostimulant alone.

The study was led by Dr. Timothy Wilens of Massachusetts General Hospital who worked with eight other researchers from various institutions.

The study was a nine week, double-blind, placebo-controlled, dose-optimization study with participants from 59 study sites with ADHD patients who all continued their stable dose of psychostimulants administered in the morning but were randomly chosen to receive GXR either in the morning, in the evening or a placebo.

Researchers reported that participants who received combinations of psychostimulants and GXR for both morning and evening administration showed significant improvements from the baseline to endpoint measured on the ADHD-Rating Scale IV total score compared to ones who were given a placebo plus psychostimulant.

Results indicated particular improvements in the inattention, hyperactivity, and impulsivity subscales of the rating school for subjects given a combination of GXR and psychostimulant, and no new safety risks surfaced with the combination therapy.

"The results of this study support the hypothesis that adjunctive administration of the selective alpha2A-adrenoceptoragonist, GXR, to a psychostimulant in subjects with suboptimal response to psychostimulants reduces ADHD symptoms over placebo with a psychostimulant," Wilens and his team said in a statement.

The study will be published in the January 2012 issue of the Journal of the American Academy of Child and Adolescent Psychiatry.