levamisole

Levamisole, marketed under the brand name Ergamisol, is an antiparasitic medication primarily used to treat worm infestations in animals. In the past, it was also prescribed for human use as an immunomodulatory agent in the treatment of rheumatoid arthritis and as an adjunct therapy for colorectal cancer. However, it is no longer approved for human use in the United States.

Today, levamisole is most commonly encountered as an adulterant in cocaine. As a result, individuals exposed to levamisole are often people who use cocaine.