A Triple-Acting Peptide Drug Reduced Fentanyl Use and Craving in Rats

Rats were allowed to self-administer intravenous fentanyl (2.5 μg/kg per infusion) for 21 days to establish addiction-like behavior. They were then pretreated with either vehicle or GEP12 (1.57 or 12.53 μg/kg, injected into the abdomen) before test sessions measuring drug-taking and drug-seeking. In vivo fiber photometry was used to measure real-time dopamine release in the nucleus accumbens during fentanyl self-administration.

The opioid crisis has limited effective pharmacotherapies. Current medications like methadone and buprenorphine target opioid receptors directly, but this study explores a completely different approach — using peptide-based drugs that act on appetite and reward circuits. The fact that a GLP-1-based triple agonist can reduce opioid-seeking without causing nausea or food suppression opens a potential new treatment avenue for opioid use disorder.

This study builds on a growing body of evidence suggesting GLP-1 receptor agonists (like semaglutide) may reduce addictive behaviors beyond food. By combining GLP-1 activation with neuropeptide Y receptor targeting, the triple agonist approach may provide stronger anti-addiction effects while minimizing the nausea that limits single GLP-1 drugs. It represents a new pharmacological class for treating substance use disorders.

This is an animal study using rats, and the results may not translate directly to humans. The study did not test long-term safety or efficacy, and the specific doses used in rats would need to be recalculated for human trials. The reinstatement model is an approximation of human relapse, not a perfect analog.