A cocaine user was admitted to a Boston area hospital recently with agranulocytosis, a serious, acute blood disease characterized by low white blood cell counts. Agranulocytosis may be associated with fever and ulcerations of the mucous membranes, as well as immune compromise and infections. The cause appeared to be associated with cocaine that had been cut with levamisole. Levamisole has been used in veterinary medicine in the de-worming of animals. It was used in human medicine in the past for treating autoimmune diseases and cancer, was not very effective, had severe adverse events associated with it, and is no longer an approved drug for human use.
Levamisole is likely added to the cocaine product at the point of production outside of the United States, though it is not understood why. It can seriously reduce a person's white blood cells, suppressing immune function and the body's ability to fight off even minor infections. People who snort, smoke, or inject crack or powder cocaine contaminated by levamisole can develop overwhelming, rapidly developing, and life threatening infections. Other serious side effects also occur.
Cocaine users with potentially life-threatening agranulocytosis have presented in various cities in the U.S. and Canada. Some evidence suggests that levamisole used to adulterate cocaine may be causing a drug-induced effect on the bone marrow. Studies of cocaine from street sources have revealed adulteration with levamisole in up to 30% of samples; so many users might be at risk.
Investigational methods to test for the presence of levamisole in urine or samples of cocaine are available, but the drug is quickly eliminated and urine must be collected as close as possible after last exposure to cocaine. The agranulocytosis is reversible with the elimination of exposure to levamisole and these patients should respond to usual treatment for agranulocytosis.