CHICAGO - Despite recommended limits on codeine use in children, the potent painkiller is prescribed for children in at least half a million emergency room visits each year, a study suggests.

Use of the drug in that setting is hardly rampant - just 3 percent of kids' ER visits resulted in a codeine prescription in 2010, the 10-year study found. But with more than 25 million ER visits by children each year, the authors say far too many kids are getting the drug when better options are available.

The concerns

Codeine is an opiate drug and a genetic variation makes some people metabolize it too quickly, potentially resulting in dangerous side effects including excessive sleepiness and difficulty breathing. The Food and Drug Administration issued its strictest warning last year about a rare risk for life-threatening complications or death in children given the drug after certain surgeries. It advises using codeine for children's pain only if anticipated benefits outweigh the risks.

Another genetic variation makes the drug ineffective for pain relief in as many as a third of patients. Codeine was once commonly used for coughs, but the American Academy of Pediatrics recommends against that use because of the risks and no evidence it relieves coughs.

The fine print

Injuries and respiratory symptoms are the top reasons for children's ER visits. The study authors analyzed 2001-10 national data on ER visits for kids aged 3 to 17. The portion of visits where codeine was prescribed dipped slightly during the study. But the authors estimated the yearly number of codeine visits ranged from almost 560,000 to 877,000. Information on any side effects was not included in the data.

The study was published online Monday in Pediatrics.

What do doctors say?

Dr. Kathleen Neville, a pediatric drug expert at Children's Mercy Hospitals and Clinics in Kansas City, said it's likely the numbers have declined since the study ended, given the FDA's black box warning.

Dr. Bradley Berg, medical director of McLane Children's Clinic in Round Rock, Texas, said some ER doctors may have been unaware of pediatricians' guidelines on limiting codeine's use, or recalled getting the drug themselves as children, when its use was more common, with no ill effects.

Dr. Alfred Sacchetti, a spokesman for the American College of Emergency Physicians, says codeine can be safely used in many children, especially older kids. Children typically are monitored in the ER after getting codeine and would not be sent home with a prescription if they had a bad reaction or it didn't work, he said.

The advice

Children on codeine who develop breathing problems or unusual sleepiness should get immediate medical attention, the FDA says. The study's lead author, Dr. Sunitha Kaiser, an associate pediatrics professor at the University of California, San Francisco, says doctors and parents should know about codeine's drawbacks and that alternatives are available, including dark honey for coughs in children over age 1; and ibuprofen or the opiate drug hydrocodone, for pain including broken bones.