MAJORITY OF U.S. COCAINE SUPPLY cut with veterinary deworming drug. “Cocaine’s a hell of a drug, and even more so when laced with another drug that’s commonly used to deworm opossums. Federal agents have found that 69 percent of cocaine shipments seized entering the United States contain levamisole, a veterinary drug linked to serious weakening of the immune system in humans. Here’s the real funny part: no one knows why.”