Trends in poisonings involving ketamine in the United States, 2019-2023

Off-label prescribing of ketamine to treat psychiatric disorders has been increasing, as has recreational use and availability of illicit ketamine. It is important to examine trends in ketamine-related poisonings to inform public health efforts.

We examined data from poisonings (exposures) involving ketamine reported to Poison Centers in the US between 2019 and 2023 (n = 1519). Annual trends were examined for number of exposures and characteristics of exposures, and we delineated correlates of major (life-threatening) adverse effects and death compared to less severe outcomes.

The number of reported ketamine exposures increased from 205 in 2019 to 414 in 2023. Most cases involved ketamine ingestion (57.2 %), and a plurality involved misuse or "abuse" (36.2 %) and moderate effects (44.8 %). The percentage of cases involving suspected suicide attempts doubled from 12.7 % in 2019 to 25.9 % (a 103.9 % increase; P < 0.001); ingestion use increased from 46.0 % to 65.2 % (a 41.7 % increase; P < 0.001), and cases involving ketamine in liquid form decreased from 65.1 % to 41.2 % (a 36.7 % decrease; P < 0.001). Cases with major effects or death decreased from 23.4 % in 2019 to 15.6 % in 2023 (a 33.2 % decrease; P = 0.039). A major event or death was experienced by 18.6 % of cases, but prevalence was lower for those who inhaled ketamine (aPR=0.49, 95 % CI:0.29-0.85) compared to those who did not inhale.

Poisonings involving ketamine are at their highest in reporting history. Both medical and recreational ketamine use and related adverse events need to be monitored, especially as off-label prescribing of take-home oral formulations appears to be increasing.