Monitoring illicit pentobarbital availability in the United States: A National Drug Early Warning System briefing

Background: Pentobarbital is a Schedule II/III short-acting barbiturate with limited medical use in humans. Veterinary professionals use pentobarbital to euthanize dogs, cats, and other companion animals. Pentobarbital is also utilized in capital punishment and small amounts are illegally shipped or diverted to assist in suicides. However, five kilograms of pentobarbital smuggled in from Mexico was recently seized by an organized crime drug enforcement task force (along with fentanyl, heroin, and cocaine), which may suggest a shift in illicit supply. We investigated potential indicators of illicit pentobarbital use or availability in the US to help determine whether this drug is becoming an emerging public health concern. Methods: The National Drug Early Warning System requested information on pentobarbital from its sentinel surveillance sites and collaborators and conducted a search of current literature. Results: In early 2024, multiple batches of counterfeit pills (e.g., pressed as "M30s" to represent oxycodone) confiscated near the Southwest border tested positive for pentobarbital plus combinations of fentanyl, fentanyl analogs, and xylazine. Other indicators suggest pentobarbital is being smuggled in powder form and possibly sold as another drug such as heroin. One national drug analysis program detected pentobarbital in 217 drug submissions from 2020 to 2023, and there were at least 12 fatal exposures linked to use from 2020 to 2022. Conclusion: Continued monitoring of illicit use and availability is needed as pentobarbital may continue to appear on the illicit market. Unknown exposure can occur if the drug is mixed into counterfeit pills or sold in powder form represented to be another drug.