There is an urgent need for better pain-relieving drugs that aren't addictive. Currently, more than 100 Americans die from opioid overdoses every day.

A new compound could offer the pain-relieving properties of opioids without tolerance or addictive properties, according to animal tests conducted at the University of Michigan.

"The chronic pain problem in America is a financial burden to the tune of over 100 billion dollars a year. It is the most cited reason for missed work. One of the best known ways currently to treat pain is with opioids. Unfortunately, opioid activation creates a myriad of negative side effects including tolerance. Tolerance is when more drug is needed to achieve the same effect," Tomás Joaquín Fernández, a postbaccalaeureate scholar in the University of Michigan Department of Pharmacology and Edward F Domino Research Center, explained to ALN.

"If more drug is given, that potentially means more severe side effects. If we can create a compound that significantly reduces tolerance development, it bodes well for individuals who have life long chronic pain. They will need less medication, and potentially have less negative side effects."

The researchers engineered compounds modeled after the body's own pain-relieving peptides to interact at two opioid receptor types. One type is responsible for pain relief and addiction liability. The other can be employed to reduce addiction liability and tolerance development.

One of these compounds were tested in laboratory mice, producing pain-relieving effects. The compound was not effective in tests for reward and dependence, two effects that can lead to addiction and withdrawal

This research was presented at the American Society for Pharmacology and Experimental Therapeutics annual meeting during the 2018 Experimental Biology meeting.