NIH Identifies DFNZ, a Potent Opioid With Strong Pain Relief and Fewer Risks in Animals

Overview

• NIH reported in Nature that DFNZ, from a nitazene family shelved in the 1950s, produced strong pain relief in rodent tests.
• At therapeutic doses in rats, the drug did not depress breathing and showed no tolerance, dependence, or meaningful withdrawal.
• Rats worked to self-administer DFNZ, yet drug-seeking stopped when saline replaced the drug, unlike patterns seen with heroin or fentanyl.
• Brain measurements showed slow dopamine release in reward circuits without the rapid spikes linked to strong drug cues and craving.
• The team plans more animal studies before seeking approval for human trials, and they propose testing DFNZ for opioid use disorder as well as pain.