Injectable horse dewormer throws aminorex false positives

In a follow-up to a previous story on the aminorex doping scandal in horse racing, it turns out that an injectable worm medicine may be the culprit for the current rash of horses testing positive for aminorex. From a news release at TheHorse.com:

Using the same standard procedures for the detection of aminorex it was found that when a commonly used over the counter anthelmetic, injectable levamisole phosphate, is assayed directly from the original container, the laboratory reported that it contains a substance that has a similar molecular weight to aminorex. However, it has a different extraction time, which indicates that it is not aminorex. Other commercially available products, including the non-injectable forms of levamisole, were not found to contain this same compound using the same analytical procedures.

Also, when they gave horses the suspect medicine and tested their urine, turns out they tested positive for aminorex. So what does this tell us? First of all, we should always be wary of false positives in any drug testing. Most commercial drug testing kits will throw a positive for opiates if you've recently eaten a poppy-seed bagel, or a positive for stimulants if you recently took cold medicine. The owners of the suspended horses have basically been living their worst nightmares for a couple of weeks now, and the whole circuit has been thrown into a tizzy over some bad chemistry. There are cases where humans who have been discriminated against due to false positives have sued and won big damages from employers and firms who make the kits. This latest round of doping hysteria in the horse racing community may be over, but it is a telling lesson in how people tend to over-react at the slightest whiff of a drug scandal.