THE EFFECT OF THE STIMULANT DRUGS DEXTROAMPHETAMINE AND METHYLPHENDIATE ON GROWTH HORMONE SECRETION IN HYPERACTIVE CHILDREN

Abstract

Recent reports that prolonged use of the stimulant drugs dextroamphetamine and methylphendiate (Ritalin) in high doses can suppress growth in hyperactive children and that rebound growth occurred after cessation of therapy, prompted us to test whether these two drugs could provoke growth hormone (GH) secretion. The effect of L-dopa (l25–500 mg) and 15 mg of amphetamine on GH secretion was studied in 10 hyperactive children. Each of the children had both tests performed on alternate days, and serum GH was determined at 0, 30, 60, 90, 120 and 180 min. Individuals with a peak serum GH level of less than 6 ug/ml were considered “non-responders”. There were two non-responders to each drug, and one child did not respond to either test. Peak GH response occured at 60 min in both tests with a mean peak CH level of 11.7 ug/ml after L-dopa and 9.8 ug/ml after amphetamine. There were no significant differencesbetween the mean values at any time of sampling. Preliminary data indicate that methylphendiate also can provoke GH secretion to similar extent as amphetamine. We are now in progress to retest the effect of these drugs on GH secretion in children who have been on methylphendiate treatment for 6 months or more.