Ketamine in U.S. Overdose Deaths, 2019–2023

Ketamine is a Schedule III controlled substance approved by the Food and Drug Administration for general anesthesia. It can cause mild hallucinogenic effects as well as breathing, heart and neuropsychiatric problems. In 2019 the FDA approved a form of it, esketamine, for adults with treatment-resistant depression, and wider availability has led to more use. Ketamine use, poison center calls about it and law enforcement drug reports all rose through 2019 — but how often it figures in fatal overdoses was not known.

CDC researchers looked at data from the State Unintentional Drug Overdose Reporting System (SUDORS), which combines death certificates, medical examiner and coroner reports and postmortem toxicology, for overdose deaths of unintentional or undetermined intent from July 2019 through June 2023. A drug was counted as detected if toxicology found it or its metabolites, and as involved if it was listed as a cause of death.

What they found

Ketamine was rare. Across 45 jurisdictions (44 states and Washington, D.C.), there were 228,668 overdose deaths. Ketamine was:

• detected in 912 (0.4%);
• involved in 440 (0.2%);
• the only drug involved in just 24 (0.01%).

It almost always came with other drugs. Among deaths with ketamine detected:

Who died: about a third (34.8%) were aged 25–34; about three-quarters were male (71.3%) and non-Hispanic White (73.7%).

But it was rising. In the 28 jurisdictions (27 states and D.C.) with data for the whole period, the number and share of overdose deaths with ketamine detected climbed from 47 (0.3%) to 107 (0.5%) over the period, with notable increases as early as July–December 2020.

Limits

• The source of the ketamine — bought illegally or prescribed — is unknown.
• The data cover a subset of jurisdictions and may not represent the whole country.
• Toxicology testing varies within and between jurisdictions, and ketamine isn't always on testing panels, so it may be undercounted.

Why it matters

Ketamine still accounts for a small share of overdose deaths, but its detection is growing. As polysubstance use rises, and as ketamine is used more for treatment-resistant depression and in compounded formulations, the authors call for continued monitoring to catch changes in its role in overdose deaths and to better understand the drug interactions and circumstances behind them.

Sources

• Vivolo-Kantor AM, Mattson CL, Zlotorzynska M. "Notes from the Field: Ketamine Detection and Involvement in Drug Overdose Deaths — United States, July 2019–June 2023," MMWR Vol. 73, No. 44, CDC; a work of the United States government in the public domain.