FDA regulators have updated the warning labels on methylphenidate products such as Ritalin, Focalin and Concerta to reflect reports of prolonged, painful erections (priapism) associated with the drugs. The age range of patients who experienced the effect was 8 to 33, with an average age of 12. In some cases surgery, a shunt, or needle aspiration were necessary to remove blood from the penis. Priapism is even more commonly associated with non-stimulant ADHD drugs such as Strattera, the regulators warned.
Of further interest:
Painful Erections Linked to ADHD Drugs Including Ritalin by FDA (Bloomberg Businessweek)