WASHINGTON (AP) — Federal health advisers have unanimously rejected an experimental pain pill that combines two common opioids, oxycodone and morphine.

The combination pill, Moxduo, was developed by QRxPharma with the aim of decreasing dangerous side effects of prescription painkillers, including breathing problems, nausea and vomiting. The company theorized that combining lower doses of the two drugs would be safer and more effective than taking higher doses of the drugs separately.