A few years ago, The Stranger ran a series of articles on a mysterious additive to the world's cocaine supply—levamisole, a de-worming agent used in livestock (and sometimes people) that causes some people's immune systems to crash, leading to infections (minor and major), tissue necrosis, and sometimes death.
There were several strange things about levamisole—it's not the world's cheapest cut, it wasn't being used by one big crime syndicate but popped up independently in lots of little ones nearly simultaneously—but the biggest mystery is why it was being cut into the cocaine in South America before it was smuggled into the US either by sea or overland through Mexico.
Typically, drugs are made and shipped in a relatively pure state (less volume means less chance of detection) and cut when they reach their destination market. Why would Mexican smugglers, for example, be willing to buy bulked-up cocaine off of Colombian manufacturers and cart that around instead of the pure stuff?
Nobody had the answer—not the DEA, not drug scholars, not scientists—but there were some going theories. One was that levamisole acted synergistically with cocaine, providing more high with less land- and labor-intensive coca growing. Another was that levamisole, unlike other additives, passes crude purity tests allowing one to sell bulked-up product that acts like pure product. A third was that it behaves like cocaine during the crack-making process—normally, cooking up rock burns impurities out of cocaine, meaning levamisole would be the rare bulking agent that would remain a bulking agent (and therefore increase profits) even if the powder is cooked into crack.
The wheels of science turn more slowly than journalism (thank goodness), but a new paper from researchers at Temple University provides some good evidence to support the first theory—that levamisole is synergistic with cocaine. (Being able to make drugs in a lab instead of on a farm is attractive to manufacturers because it requires less labor and acreage, reducing costs and chances of getting caught.)
The researchers gave pure cocaine, pure levamisole, and a cocaine-levamisole mix to planarians, a species of non-parasitic flatworm. Their results:
In conditioned place preference (CPP) experiments, cocaine produced a significant preference shift; in contrast, levamisole was ineffective at all concentrations tested. For combination experiments, a submaximal concentration of cocaine produced CPP that was enhanced by inactive concentrations of levamisole, indicating synergism. The present results provide the first experimental evidence that levamisole enhances cocaine's action in vivo. Most important is the identification of synergism for the levamisole/cocaine interaction, which now requires further study in mammals.
This experiment may show up on some knuckle-dragger's year-end list of dumb science experiments (guh guh, they gave cocaine to worms, guh guh) but these findings are a huge first step towards a better understanding of not just of neurology and pharmacology, but why some drug users are getting sick and dying, as well as the current mechanics of the world cocaine trade.
And it scientifically verifies what, back in 2010, had just been an educated guess.
Thanks to drug-policy expert—and prolific Twitter user—Sanho Tree for the tip.