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TUESDAY, Dec. 17, 2013 (HealthDay News) -- In rare cases, Ritalin and some other drugs used to treat attention-deficit/hyperactivity disorder (ADHD) can cause long-lasting and sometimes painful erections, the U.S. Food and Drug Administration said Tuesday.
If this condition -- called priapism -- is not treated immediately, it can cause permanent damage to the penis.
The class of ADHD medications that have been linked to priapism include methylphenidates, which are central nervous system stimulants. They go by the brand names Ritalin, Concerta, Daytrana, Focalin, Metadate, Methylin and Quillivant.
A non-stimulant ADHD drug called Strattera (atomoxetine) has also been linked with priapism in children, teens and adults.
Based on a recent review of these products, the FDA has told manufacturers to update the drugs' labels and patient medication guides.
"There have been very few case reports on this adverse effect in association with drugs to treat ADHD," said one expert, Victoria Richards, an associate professor of medical sciences at Quinnipiac University in North Haven, Conn.
"Although the effect is rare, the warning will at least draw attention to the potentially dangerous connection, not only in light of improved recognition and diagnosing of ADHD, but also in the misuse/abuse of those stimulant drugs," Richards said.
Priapism appears to be more common in patients taking Strattera than in those taking methylphenidate products, but a lack of data means that the FDA does not know how often priapism occurs in patients taking either type of drug.
Priapism can occur in males of any age. It happens when blood in the penis becomes trapped, resulting in an abnormally long-lasting and sometimes painful erection.
Doctors should make sure that male patients and their parents know the signs and symptoms of priapism and the importance of immediate medical treatment, the FDA said.
The agency noted that younger males, especially those who haven't reached puberty, may not recognize the problem or may be too embarrassed to tell anyone about it. Patients should be encouraged to read the medication guide that comes with these products.
It's also important for doctors to use caution when switching patients from methylphenidate to Strattera, and patients should not stop taking a methylphenidate product without first discussing it with a doctor, the FDA said.
ADHD, a neurological behavior disorder, is usually diagnosed in childhood and often lasts into adulthood. Kids with ADHD may have trouble paying attention and controlling impulsive behaviors. These medications are intended to help them focus and control their actions.
The American Urological Association has more about priapism.