From October 15 to December 31, 2015, the California Poison Control System–San Francisco division identified 8 patients who experienced adverse effects associated with the ingestion of counterfeit alprazolam tablets found to contain fentanyl and, in some cases, etizolam. The identification of these patients resulted in a coordinated response that included state and local public health departments, a toxicology laboratory, and media outlets, and resulted in an investigation by local law enforcement agencies.
Arens AM, van Wijk XMR, Vo KT, Lynch KL, Wu AHB, Smollin CG. Adverse Effects From Counterfeit Alprazolam Tablets. JAMA Intern Med. 2016;176(10):1554-1555. doi:10.1001/jamainternmed.2016.4306