Kids with a broken arm get better pain relief with ibuprofen than on more powerful prescription combination that includes the narcotic codeine, a new study finds.

The study is among the first to provide parents and pediatricians with clear evidence on what works for fracture pain, since there have been few previous studies to compare pain reliever effectiveness in children.

The study compared ibuprofen (sold as Advil, Motrin and other brands) against the prescription of acetaminophen plus codeine, a combo called Tylenol No. 3 that is also sold in generic form.

It looked at 336 children aged four to 18 who were given the painkillers in the first three days after being treated for a broken arm at Children's Hospital of Wisconsin.

The researchers, led by Dr. Amy Drendel of the Medical College of Wisconsin, found that the children on ibuprofen fared better, they report in the Annals of Emergency Medicine. The kids reported higher levels of satisfaction, had better use of their broken arm and fewer side effects.

In fact, in the ibuprofen group, only 29.5 per cent reported an adverse effect, compared with 50.9 per cent of the acetaminophen with codeine group.

Additionally, almost 90 per cent of children treated with ibuprofen preferred the same treatment for future fractures, compared with only 72 per cent of the acetaminophen with codeine group.

The study should help assure and parents and health care providers that a simple and inexpensive over-the-counter medication is effective in relieving the pain of fractures in children.

"Our study calls into question the practice of using acetaminophen with codeine as a rescue medicine if ibuprofen fails to treat fracture pain for children," Dr. Drendel said in a statement.

"The majority of children with simple arm fractures have pain at home significant enough to result in analgesic administration and our study helps clinicians make an informed decision about what medication will work best for children with these injuries once they are sent home," said Drendel.

The study did not compare the painkillers in relieving other kinds of pains besides fractures.