Chicago ? Deciding which medicine to give a child in pain just got easier: The first head-to-head study of three common painkillers found that ibuprofen works best, at least for kids with broken bones, bruises and sprains.

Available generically and under the brand names Advil and Motrin, ibuprofen beat generic acetaminophen and codeine in an emergency room study of 300 children treated at a Canadian hospital.

The youngsters, aged 6 to 17, were randomly assigned to receive standard doses of one of the three medicines. They then periodically rated their pain. Half an hour later, ratings were similar in the three groups. But starting an hour after taking the medicine, children who got ibuprofen reported substantially greater pain relief than the other two groups.

Children rated their pain on a 100-point scale before and after taking the medicine. At 60 minutes afterward, scores for children who got ibuprofen had dropped 24 points, compared with 12 points for the acetaminophen group and 11 points for the codeine group. The differences remained at 120 minutes.

The study was done at Children’s Hospital of Eastern Ontario in Ottawa, and a research institute at the hospital funded the study. Results appear in the March edition of Pediatrics, being released today.

The study sheds light on two common problems in pediatrics – children with broken bones, sprains and strains, and “what should we give them” for pain, said Dr. Catherine Skae, a pain specialist at Children’s Hospital at Montefiore Medical Center in New York. “It’s good that somebody looked at it systematically.”

For parents, choosing a painkiller for kids can be confusing, partly because acetaminophen, sold as Tylenol, and ibuprofen both work against fevers. Codeine does too, but it’s a mild narcotic available only by prescription.

The study should ease that dilemma, said lead author Dr. Eric Clark of the University of Ottawa.