Evaluating clonidine response in children and adolescents with attention-deficit/hyperactivity disorder

Abstract

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in childhood, which is generally treated with stimulant and non-stimulant medications. However, 10-30% of patients in clinical setting do not present with adequate response to initial stimulant treatment. Thereby, clonidine may be considered for those patients who have failed to respond to psychostimulant/atomoxetine monotherapy or as an augmentation for inadequate response/comorbidity. This observational study evaluated its effectiveness as a single drug in ADHD cases unresponsive to previous treatment trials. Seventeen ADHD cases that were non-responders to stimulant, non-stimulant and combination therapy for the primary symptoms of ADHD were included in the study. Four cases dropped out before follow up, leaving thirteen cases who were administered immediate release clonidine treatment alone with a mean dose of 0.2 +/- 0.05 mg/day at baseline. The trial lasted for 12 weeks, and treatment outcomes were evaluated by the Turgay DSM-IV Based Child and Adolescent Behavior Disorders Screening and Rating Scale (T-DSM-IV-S) and the Clinical Global Impressions-Severity (CGI-S) and Improvement (CGI-I) scales. Mean age of the sample was 12.5 years (SD = 3.0) and eleven of the subjects had another comorbid psychopathology. Only two cases were evaluated as "very much improved", while another patient was judged to be "minimally improved" after 12 weeks of clonidine treatment. Attrition during follow-up was associated with higher median scores on the hyperactivity and impulsivity subscales (Mann-Whitney U test, p = 0.02). According to the T-DSM-IV-S, CGI-S, and CGI-I scales, clonidine treatment by itself had minimal benefits in this sample of treatment of refractory cases with ADHD evaluated at the study center. Clonidine is not available in Turkey pharmaceutical marketing system and patients' access to drug is limited. Our results provide first data regarding the use of clonidine in Turkish ADHD patients.