The U.S. Food and Drug Administration (FDA) warned some drugs used to treat attention deficit hyperactivity disorder (ADHD) could cause prolonged erections in some rare cases.
The FDA released a warning that methylphenidate products could lead to a painful erectile condition called priapism, the administration reported in a news release.
The FDA continued to monitor the safety of the drug after its release; upon discovering the rare but uncomfortable side effect they updated the warning labels to mention the risk of priapism.
The administration warned that anyone taking methylphenidate that experiences an erection lasting longer than four hours should seek "immediate medical attention" to avoid permanent damage to the penis.
Priapism usually occurs when blood gets trapped in the penis; the condition is particularly dangerous to prepubescent males who do not understand the possible health consequences associated with a prolonged erection or are too embarrassed to tell an adult.
The FDA recommends that anyone taking methylphenidate, including younger males, should be educated about the possible side effect.
In the methylphenidate review researchers found the median age of those prescribed the drug was 12.5 years, with an age range of eight to 33.
Some of the patients suffered from priapism after increasing their dosage of methylphenidate; in other cases the condition occurred after when the dosage was temporally stopped or there was a long period of time between doses.
"Two patients required surgical intervention; one required shunt placement, and the other had to have needle aspiration of the corpus cavernosum," the news release reported.
The FDA warned physicians that switching patients to Strattera (atomoxetine), a non-stimulant that also treats ADHD, may not solve the problem. Strattera has also been linked to some rare cases of priapism.
"Priapism appears to be more common in patients taking atomoxetine than in patients taking methylphenidate products. Health care professionals should be cautious when considering changing patients from methylphenidate to atomoxetine," the news release reported.
There have been four reported cases of patients that took Amphetamines (which is also used to treat ADHD) experiencing priapism, but all of these patients had also been taking other drugs linked to the condition.
