Researchers have found a potentially nonaddictive opioid, DFNZ, a new medicine derived from a class of drugs once considered too dangerous to study. The drug could potentially offer patients with chronic pain and injuries the benefits of an opioid without the threat of addiction or withdrawal. DFNZ's properties, including its high efficacy at treating pain, its limited brain entry and its distinct cellular signaling profile, could provide a new blueprint for designing safer analgesics or pain medications. The study also found that DFNZ reduced rats' desire for heroin, suggesting it could potentially be used as a treatment for opioid use disorder. However, more research is needed before the safest and most effective opioid can be developed.