The U.S. Food and Drug Administration has approved the use of opioid painkiller OxyContin in patients aged 11 to 16 who have not benefited enough from alternatives.

The long-acting drug is already used to treat adults suffering from around-the-clock pain and has been reformulated over the years to combat rising prescription drug abuse in the United States.

Unlike for adults, doctors are to prescribe the medicine only for children who can already tolerate a minimum dose of 20 milligrams of oxycodone, the active drug ingredient in OxyContin, the agency said, but retained the same set of warnings and precautions.

As few pain treatments come with pediatric safety and effectiveness information, doctors are forced to rely on their own experience to interpret adult data into dosing information for children.

The U.S. regulator has been stepping up efforts to procure more data on drugs for children by incentivising data collection.

Accordingly, the FDA had asked Purdue Pharma LP, which makes OxyContin, to evaluate the use of the drug in children.

The company said is in talks with the FDA regarding securing an additional 6 months of exclusivity for the drug, which goes off patent in 2030.

OxyContin accounted for about 2 percent of the 215 million prescriptions written for opioids last year, according to IMS Health.

About 39,000 prescriptions for extended-release opioids are written for patients aged 10-19 annually in the United States, Purdue said.

The original formulation of OxyContin, first approved nearly two decades ago, was withdrawn due to its potential for abuse.

The only other long-acting opioid option for pediatric pain management is the duragesic patch, which releases an opioid called fentanyl through the skin.