Cocaine users are putting themselves at risk of haematological disorders because the illicit drug is routinely ‘cut’ with levamisole, Victorian researchers say.
The anti-helminthic drug is known to cause agranulocytosis and is commonly used overseas for ‘cutting’ or bulking out illicit cocaine, since it is believed to have some neurostimulant properties as well as enhancing the appearance of the cocaine powder as “pure”.
Levamisole was previously marketed as an immunomodulator for cancer and rheumatoid arthritis patients but its propensity to cause neutropenia in up to 10% of patients led to its withdrawal from the market about 20 years ago. However it is still available as a cheap veterinary anti-helminthic product.
Since levamisole is widely found as a cocaine adulterating agent in the US, Victorian researchers investigated whether it was also present in Australian users.
In an analysis of urine drug screen tests performed in emergency department patients they detected levamisole in 27 of 36 (75%) urine samples that tested positive to high levels of cocaine. Levamisole was not detected in tests of thousands of samples that were negative for cocaine.
The researchers said the presence of levamisole in the urine of Australian cocaine users shows they are at risk of the blood disorders frequently reported in the US and other countries where cocaine use is common.
They note there has been a rise in cases of unexplained infections in cocaine users in the US, which started around the same time as levamisole was incorporated into cocaine supplies.
“Since then a number of medical conditions have been linked to levamisole-adulterated cocaine including vasculitis, glomerulonephritis, haemorrhagic skin necrosis, neutropenia and agranulocytosis. More recently, there have been several published fatal case reports [of agranulocytosis] likely attributable to levamisole,” they write in Pathology.
Among the Australian patients tested positive for levamisole, one 29-year old female had an unexplained low neutrophil count of 1.5 x 109. The patient’s neutrophil count normalised when she was followed up several months later.
The researchers say that with 2.5% of the Australian population estimated to have used cocaine, there is potential for adverse haematological adverse effects from widespread levamisole adulteration.
“Considering the known side effects of levamisole, increasing cocaine use is likely to pose a public health issue in the future,” they conclude.