Xylazine potentiates the interoceptive effects of fentanyl in male and female rats.

Rationale: Xylazine, a sedative typically used in veterinary medicine, has been increasingly detected as an adulterant in the unregulated opioid supply and present in opioid overdose deaths. Therefore, xylazine-adulterated fentanyl is a growing public health concern. People who use drugs have reported that xylazine changes and prolongs the effects of fentanyl.