The Food and Drug Administration (FDA) announced this week that it would crack down on imports of xylazine, a non-opioid veterinary sedative used on animals ranging from dogs and cats to deer and elk. The FDA is targeting the drug because black-market sellers have added it to various illicit fentanyl mixtures; the FDA said it has also turned up mixed with stimulants like cocaine and methamphetamine. If ingested by humans, xylazine "can depress breathing, blood pressure, heart rate and body temperature to critical levels"; if injected, it can cause tissue decay requiring amputation. It's also known by the street names "tranq" and "zombie drug."
The FDA's new alert authorizes import authorities to "detain without physical examination shipments of xylazine" and any drugs which contain xylazine. The agency's announcement specified that it intends to "prevent the drug from entering the U.S. market for illicit purposes, while maintaining availability for its legitimate uses in animals."
However, government efforts to ensure certain drugs are used only for specific purposes have proven fruitless because prohibition incentivizes circumvention: When it's hard to procure a particular substance, drug traffickers will get the most potent version of it they can find, as a smaller and more easily concealed quantity can be parceled out further over a more significant number of sales.
This is why fentanyl is used in black-market opioids in the first place. Users did not demand a substance that is 40 times more potent than heroin for recreational use; prohibitionist policies made it more challenging to procure pain medication, leading pain patients to seek out heroin. Heroin, however, is a crop drug, which makes it expensive to produce, ship, and buy. Fentanyl is synthetic, making it cheaper to produce, ship, and buy. When the law makes it harder to get legal pain pills, everybody adapts, and you get illegal fentanyl with no quality control.
Similarly, users of illicit drugs aren't clamoring for animal tranquilizers—drug dealers are just adapting to market conditions.
The FDA's regulatory actions on xylazine may sound reasonable, but government prohibition created the problem, and more prohibition won't solve it.