Juvenile male rhesus monkeys given methylphenidate hydrochloride, a drug widely used to treat attention-deficit/hyperactivity disorder, exhibited delayed progression of puberty, according to a recent study (Mattison DR et al. Proc Natl Acad Sci U S A. 2011;108:16301-16306).
Investigators from the National Institutes of Health and other institutions observed these changes in monkeys after 14 months of treatment with the drug. Also, testicular descent was significantly delayed in monkeys receiving high doses of the drug twice daily for 40 months; these animals and a group receiving a low dose had lower blood testosterone levels through month 33 of treatment. Starting the drug before puberty delayed testicular development.
Hampton T. ADHD Drug May Affect Puberty. JAMA. 2011;306(17):1853. doi:10.1001/jama.2011.1573