The 5α-Reductase Inhibitor Finasteride Reduces Opioid Self-Administration in Animal Models of Opioid Use Disorder

The study demonstrated that finasteride, a 5α-reductase inhibitor, significantly reduced opioid self-administration in both zebrafish and rat models. In zebrafish, finasteride reduced hydrocodone self-administration by 73% at concentrations as low as 5 nM, and in rats, it reduced hydrocodone self-administration at doses of 50 mg/kg. The effect was consistent across different opioids, including morphine and fentanyl, and was observed in both male and female rats. Finasteride also alleviated some physical symptoms of opioid withdrawal without affecting the pain-relieving properties of opioids. The study suggested that finasteride's effects might be due to alterations in neuroactive steroid levels in the brain, highlighting its potential as a treatment for opioid use disorder.