A new synthetic opioid may pose a lower risk of addiction than morphine while still relieving pain, a study in rats has found. (Image credit: digicomphoto via Getty Images)

A new synthetic opioid designed to relieve pain could hold promise for replacing addictive painkillers like morphine or fentanyl in patients, a study in lab rats suggests.

The research hints that the new opioid carries a lower risk of addiction — though it's likely not completely risk-free.

In the 1950s, a class of highly potent opioids called nitazenes was developed and offered 1,000 times more relief than morphine , but they carried a much higher risk of overdose.…