Methylphenidate: growth retardation.

Methylphenidate is an amphetamine psychostimulant used as a symptomatic treatment for attention-deficit hyperactivity disorder. A randomised trial examined changes in the height and weight of 521 hyperactive children. After 14 months, children treated with methylphenidate had gained less height and less weight (-1.23 cm per year and -2.48 kg per year) than untreated children. After 3 years, the differences were about 2 cm and 2.7 kg. Systematic reviews have provided similar results: methylphenidate slows growth by about 1 to 1.5 cm per year. Catch-up growth usually occurs during a 2-year period after methylphenidate withdrawal. Studies of final adult height have shown no statistically significant difference versus never-treated individuals. The effect of methylphenidate on growth is probably due to its impact in reducing appetite. Dexamfetamine is sometimes used as an alternative to methylphenidate and has similar effects on growth, as is the case with atomoxetine. In practice, prescription renewal provides a good opportunity to measure these children's growth. Marked growth retardation may warrant treatment interruption or a dose reduction.