Tainted Cocaine Rotting Flesh Dealers cutting coke with dangerous livestock deworming drug By Rob Quinn, Newser Staff Posted Jun 22, 2011 1:59 AM CDT 27 comments Comments Cocaine - now with extra de-worming drugs. (Shutterstock) (Newser) – A horrifying side effect is emerging among people who use cocaine cut with a drug that deworms livestock. Users who suffer a bad reaction to the drug levamisole are developing large patches of dead, blackened skin on their faces and bodies as the additive damages blood vessels and causes skin to rot away, reports the New York Daily News. The use of levamisole to cut cocaine and other drugs has been skyrocketing in recent years, possibly because it gives users more of a buzz than other substances dealers add. In one case, a patient who had been treated "used cocaine again and developed the same skin reaction again," notes the co-author of a study. "He then switched drug dealers, and the problem cleared up."