Panel warns of emerging substances — xylazine, nitazenes and evolving analogs — and calls for nimble detection and research

Experts at the subcommittee hearing warned that synthetic drugs beyond fentanyl — including xylazine and newer nitazenes — are increasingly present in the illicit supply and that monitoring, detection and rapid response must keep pace.

"Xylazine is a potent animal tranquilizer ... it is often combined by cartel chemists with illicit fentanyl" and may increase the risk of fatal poisoning because opioid antagonists are not effective against the sedative effects, said Dr. Timothy Westlake. He and other witnesses advised Congress to consider statutory controls for xylazine and to equip laboratories and public-health monitoring to detect such compounds quickly.

Witnesses described nitazenes as highly potent opioids encountered in recent overdose deaths and noted that temporary or ad hoc scheduling of each new analog slows response. Dr. Westlake and others recommended class scheduling for categories of compounds (where scientifically feasible) and emphasized coordination with the Drug Enforcement Administration and NIH to preserve legitimate research access.

Regina LaBelle and Dr. Deepa Camenga recommended bolstering state and local drug monitoring programs that identify emerging substances and issuing rapid public-health alerts. Sheriff Michael Bouchard said forensic labs have detected rising quantities of xylazine in seized samples and called for improved interagency coordination, increased funding for forensic testing and better regulation of pill presses and precursor supply routes.

Ending: Witnesses urged a ‘‘whole-of-government’’ approach that combines monitoring, scheduling, research support, treatment availability and law enforcement to respond to evolving chemical threats in the illicit supply.