A new study shows as many as one in 20 children were still receiving codeine to treat pain after tonsil and adenoid surgery, two years after federal regulators warned doctors that prescribing the opioid to kids after the routine surgeries could be fatal. The research from the University of Chicago Medicine, the University of Michigan and Harvard University was published in the journal Pediatrics.

“We should not prescribe codeine to children, for any reason,” said Kao-Ping Chua, MD, PhD, lead author of the new study and assistant professor of pediatrics and communicable diseases at the University of Michigan. “Some children rapidly convert codeine to morphine, resulting in a risk of overdose. Other children poorly metabolize codeine to morphine, resulting in no improvement in pain. Therefore, codeine is not just potentially unsafe, but also potentially ineffective.”

In 2013, the FDA issued a “black box warning” against the use of codeine following tonsillectomies and adenoidectomies in children, due to an increasing number of reported deaths in such instances. According to Chua, who worked at UChicago Medicine while conducting the research, codeine has historically been among the most common drugs used to treat pain in children following these childhood surgeries.

“What was unclear, however,” he said, “is whether the 2013 FDA black box warning—the strongest warning the FDA can issue—was successful in completely eliminating the use of codeine in this situation.”

Chua and study co-authors Mark Shrime, MD, MPH, PhD, of Harvard University, and Rena Conti, PhD, of UChicago Medicine, reviewed a national sample of more than 300,000 privately insured children who had the surgeries between 2010 to 2015. The five-year period allowed researchers to examine at prescribing patterns before and after the FDA warning.

The team found a decrease in codeine prescriptions from the 2013 black box warning. But the practice continued: one in 20 children undergoing these surgeries were still prescribed codeine in December 2015, in spite of its well-documented safety and efficacy issues.

“The residual inappropriate codeine prescribing is consistent with other research showing that FDA black box warnings can make substantial, but incomplete, impact on clinical practice,” said Conti, who studies the effect of FDA warnings.

According to the researchers, there are safer and more effective alternatives to pain management for children who have their tonsils or adenoids removed. Many patients rely on over-the-counter painkillers like acetaminophen (sometimes known as Tylenol), which has been proven to be an effective post-surgical analgesic. Ibuprofen, despite some early concerns, has also been proven to be effective and has not been shown to increase the risk of post-tonsillectomy bleeding.

In severe cases, alternative opioids like oxycodone and hydrocodone may be effective. However, Chua said these drugs also have side effects and are prone to abuse, so the best strategy to manage post-surgical pain in children is to start with over-the-counter painkillers and only rely on opioids when absolutely necessary.

In the future, the researchers believe quality improvement efforts should focus on eliminating all inappropriate codeine prescribing and encouraging the use of effective non-opioid medications like acetaminophen and ibuprofen.

The paper is titled, “Effect of FDA Investigation on Opioid Prescribing to Children After Tonsillectomy/Adenoidectomy.”