Levamisole is a synthetic imidazothiazole compound originally developed as an anthelmintic agent used to treat parasitic worm infections in both humans and animals. Introduced in the 1960s, it gained recognition not only for its antiparasitic properties but also for its unexpected immunomodulatory effects, which prompted its later use as an adjunct therapy in conditions such as rheumatoid arthritis and, for a time, in colon cancer management. Despite its early therapeutic promise, levamisole’s medical use in humans declined due to reports of serious adverse effects, particularly agranulocytosis, although it continues to be widely used in veterinary medicine. Interestingly, levamisole also became known for its illicit presence as a cutting agent in cocaine, further highlighting its complex and varied history. Today, it remains an important antiparasitic drug in animal health while representing a noteworthy chapter in the evolution of immunomodulatory therapies.
