Illicit Opioid Drugs Are Rarely What They Seem
From quinine, fentanyl, xylazine to lidocaine today and nitrazenes tomorrow
By Mark S Gold
Published by Psychology Today on August 19, 2025
Key points
• Adulteration of drugs has been a central feature of street drug markets, including cocaine, meth, and heroin.
• Overdoses followed fentanyl’s emergence in the U.S. illicit market, largely an adulterant for heroin.
• Now illicitly manufactured fentanyl comes with “CAINES”—local anesthetics like lidocaine or procaine.
Illicit drugs aren’t tested by the FDA or pure, nor as advertised by drug dealers. Illegal drugs are cartel-driven around profit maximization, cash-only trading, and a form of entrepreneurship. Dealers cut drugs to increase bulk and maximize sales. They also adulterate drugs to boost subjective potency. In addition, dealers use other drugs to mask poor quality or maintain a texture/color.
