“From the perspective of drug traffickers, fentanyl has several advantages over heroin. It is much more potent, which makes it easier to smuggle, and it can be produced much more cheaply and inconspicuously, since it does not require opium poppies. Xylazine has similar advantages: It is an inexpensive synthetic drug that can be produced without crops. And unlike fentanyl, it is not classified as a controlled substance, which makes it easier to obtain.
American drug users are not clamoring for xylazine in their fentanyl, any more than they were demanding fentanyl instead of heroin. The use of such adulterants is driven by the economics of prohibition. And as usual with illegal drugs, consumers do not know what they are getting. Whether it is vitamin E acetate in black market THC vapes, MDMA mixed with butylone, levamisole in cocaine, or fentanyl pressed into ersatz pain pills, prohibition reliably makes drug use more dangerous.Much to the dismay of veterinarians, drug warriors alarmed by tranq have proposed treating xylazine as a controlled substance. As usual, they think the solution to a problem created by prohibition is more prohibition.”
https://reason.com/2023/08/08/prohibition-gave-us-tranq-laced-fentanyl/