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MONDAY, Feb. 6, 2023 (HealthDay News) -- Researchers have uncovered groundbreaking evidence that pharmacies in tourist areas of Northern Mexico are selling counterfeit pills containing fentanyl, heroin, and methamphetamines. The research was published online Jan. 28 in the preprint server medRxiv and has not been peer-reviewed.
The pills, mainly sold to U.S. tourists without a prescription, were passed off as controlled substances, including oxycodone, Percocet, and Adderall, the study showed. This could add to the already high number of overdose deaths from these drugs in the United States and Mexico, U.S.-based researchers said.
"These counterfeit pills represent a serious overdose risk to buyers who think they are getting a known quantity of a weaker drug," said senior study author Chelsea Shover. She is an assistant professor at the David Geffen School of Medicine at the University of California, Los Angeles (UCLA).
About 68 percent of 40 pharmacies studied in four cities in Northern Mexico had at least one controlled substance for sale without a prescription, the researchers found. These drugs were sold in either bottles or as individual pills.
The investigators found counterfeit pills containing fentanyl, heroin, and/or methamphetamine from 11 pharmacies. Nine pill samples sold as Adderall contained methamphetamine. Eight sold as oxycodone contained fentanyl. Three sold as oxycodone had heroin in them.
"It is not possible to distinguish counterfeit medications based on appearance, because identically appearing authentic and counterfeit versions are often sold in close geographic proximity," the researchers reported. "Nevertheless, U.S. tourist drug consumers may be more trusting of controlled substances purchased directly from pharmacies."
The UCLA researchers' main findings were confirmed independently by a Los Angeles Times investigation, the study authors noted in a university news release.