Cocaine

Levamisole
This chemotherapeutic/antihelminthic agent has been found increasingly in recent years to be a contaminant of cocaine. In 2016, the Drug Enforcement Agency (DEA) reported that 87% of cocaine samples tested contained levamisole, but this was lower in 2017 with 40% of samples tested containing levamisole. In 2010 a study showed that 78% of urine toxicology specimens that were positive for cocaine were also positive for levamisole.