RESPONSE TO GROWTH-HORMONE IN ATTENTION-DEFICIT HYPERACTIVITY DISORDER - EFFECTS OF METHYLPHENIDATE AND PEMOLINE THERAPY

Objective. To determine whether treatment of attention deficit hyperac tivity disorder (ADHD) with methylphenidate hydrochloride or pemoline diminishes the response to growth hormone (GH) therapy in patients wit h idiopathic GH deficiency (IGHD) or idiopathic short stature (ISS). M ethods. The National Cooperative Growth Study database was used to ide ntify patients between 3 and 20 years of age with IGHD or ISS and thos e within these groups who were treated with methylphenidate or pemolin e for ADHD. Their growth in response to GH treatment (change in height standard deviation score [SDS]) was compared with that of patients wi th IGHD or ISS who were not treated for ADHD, by using a stepwise mult iple regression analysis. Results. In the IGHD cohort, there were 184 patients who were being treated for ADHD and 2313 who were not. In the LSS cohort there were 117 patients who were being treated for ADHD an d 1283 who were not. There was a higher percentage of males being trea ted for ADHD in both cohorts. In the IGHD cohort, the change in height SDS was positively associated with the number of years of GH treatmen t, parents' heights, body mass index, and GH injection schedule, and w as negatively associated with height SDS at the initiation of GH thera py, age, and maximum stimulated GH level. The use of methylphenidate o r pemoline had a negative effect on the change in height SDS, but the magnitude of the effect was small. Similar effects were noted in the I SS cohort, but body mass index and the use of methylphenidate or pemol ine had no effect on the change in height SDS. Conclusions. Concurrent ADHD therapy is associated with a slight decrease in the change in he ight SDS during GH treatment in patients with IGHD but not in those wi th ISS. Even in IGHD, the magnitude of the effect is small and should not deter the use of such concurrent therapy.