"Zombie" Outbreak Caused by the Synthetic Cannabinoid AMB-FUBINACA in New York.

Background: New psychoactive substances constitute a growing and dynamic class of abused drugs in the United States. On July 12, 2016, a synthetic cannabinoid caused mass intoxication of 33 persons in one New York City neighborhood, in an event described in the popular press as a "zombie" outbreak because of the appearance of the intoxicated persons.

Methods: We obtained and tested serum, whole blood, and urine samples from 8 patients among the 18 who were transported to local hospitals; we also tested a sample of the herbal "incense" product "AK-47 24 Karat Gold," which was implicated in the outbreak. Samples were analyzed by means of liquid chromatography-quadrupole time-of-flight mass spectrometry.

Results: The synthetic cannabinoid methyl 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamido)-3-methylbutanoate (AMB-FUBINACA, also known as MMB-FUBINACA or FUB-AMB) was identified in AK-47 24 Karat Gold at a mean (±SD) concentration of 16.0±3.9 mg per gram. The de-esterified acid metabolite was found in the serum or whole blood of all eight patients, with concentrations ranging from 77 to 636 ng per milliliter.

Conclusions: The potency of the synthetic cannabinoid identified in these analyses is consistent with strong depressant effects that account for the "zombielike" behavior reported in this mass intoxication. AMB-FUBINACA is an example of the emerging class of "ultrapotent" synthetic cannabinoids and poses a public health concern. Collaboration among clinical laboratory staff, health professionals, and law enforcement agencies facilitated the timely identification of the compound and allowed health authorities to take appropriate action.