Carruthers et al. in 1979 reported the first case of xylazine toxicity in a 34-year-old male, who self-medicated for insomnia with injection of 1 g of xylazine. Intentional intoxication from ingesting, inhaling, or injecting xylazine has been reported. The intravenous route is the most common route of administration for those who abuse heroin or xylazine recreationally. In Puerto Rico, xylazine has increased in popularity. Its use was associated with a high number of inmate deaths at the Guerrero Correctional Institution in Aguadilla, Puerto Rico from 2002 through 2008.