Opioid pain killers like oxycodone are commonly prescribed to people recovering from surgery. But these drugs have a potentially lethal side effect that researchers have been trying to erase: respiratory depression. It's the opposite of hyperventilation, and it is one of the leading causes of death for people on opioids.

The makers of a new drug called GAL-021 promise to reverse respiratory depression, for which more than one-third of patients are at higher risk. On Tuesday, a team of researchers from Leiden University Medical Center in the Netherlands independently confirmed that GAL-021 can stimulate breathing in opioid users without causing other harmful side effects. Their findings were published in the journal of the American Society of Anesthesiologists, Anesthesiology.

"Although opioids such as oxycodone, methadone and fentanyl are commonly used to manage perioperative and postoperative pain, opioids are associated with an increased risk of adverse effects, the most serious being respiratory depression," said Dr. Albert Dahan, lead author and professor of anesthesiology, in a news release announcing the findings. "Opioid-induced respiratory depression can lead to brain damage, cardiac arrest or death."

The drug, a proprietary molecule developed by Galleon Pharmaceuticals in Pennsylvania, is not an opioid itself. Rather, it is administered in addition to the opioid to stimulate breathing. Delivered intravenously, the doctors say it blocks potassium channels in the brain that regulate breathing.

Most previous news about GAL-021 has come from statements by the company itself. Trials on animals showed that it reversed inadequate breathing in animals while maintaining pain relief. Dosage tests on humans in 2012 increased breathing up to 50 percent, helping to expel harmful carbon dioxide.

In the new study, the researchers used opioids to induce respiratory depression in 12 healthy men, decreasing their breathing capacity by 25-30 percent. Once GAL-021 was injected, however, their breathing picked up, and they expelled more air with each breath. They said the drug didn't have any bad effects on their "sedation, pain relief, blood flow or safety parameters."

"The development of potent painkillers that do not increase the risk of respiratory depression seems still far away," Dahan said. "Using an add-on drug that reverses or prevents respiratory depression caused by opioid use, without affecting pain relief, is currently our best option to treat this condition. While our data suggest that GAL-021 is an attractive alternative to other respiratory stimulants, additional studies are needed to further confirm these findings."

Source: A. Dahan, et al. Anesthesiology. 2014.