For treating persistent pain after a car crash, prescription opioid painkillers such as oxycodone (Oxycontin) are no more effective than nonsteroidal anti-inflammatory drugs (NSAID) like ibuprofen, a new study finds.

"You'd think there would be a wealth of studies comparing our 'go-to' pain meds, but there just aren't," said study lead author Dr. Francesca Beaudoin. She's an assistant professor of emergency medicine at Brown University's Warren Alpert School of Medicine and an emergency room doctor at Rhode Island Hospital.

"Now that opioids are under fire, it's forcing us to ask: 'What is the best treatment, who is it best for and under what conditions?' " Beaudoin said in a university news release.

"As an emergency physician, I prescribe these drugs all the time. Does what I am giving to people have any impact on the pain outcomes that matter to them?" she added.

To answer those questions, she and her colleagues assessed 948 people for pain six weeks after being treated in an ER and released following a car crash.

The researchers said they tried to compare cases that were as similar as possible except for which pain reliever was prescribed.

Overall, they found, the risk of persistent pain was about the same whether patients took opioids like Oxycontin or Percocet or NSAIDs such as Advil or Motrin.

But those who were initially prescribed opioids, which can be highly addictive, were 17.5 percent more likely to still be taking the drugs after six weeks, according to the study.

The results were recently published online in the journal Pain.

The next step is to try to pinpoint the characteristics that best predict which treatment is best for which patients. This could help doctors manage patients' pain while prescribing opioids only for those who really need them, Beaudoin said.

Opioid painkiller abuse is a leading public health crisis in the United States, according to the U.S. Centers for Disease Control and Prevention.