The FDA has called on pharmacists to stop compounding a treatment for Lyme disease that has been linked to at least one patient death and a number of suspected illnesses. The drug, called bismacine or chromocine, is mixed individually by pharmacists for use by injection to treat the symptoms of the tick-borne bacterial disease. According to the FDA, the substance contains high amounts of the heavy metal bismuth and is unapproved for use by humans. Agency officials said that the substance is sometimes prescribed by "alternative health doctors."