A widely sold tube of ivermectin paste for horses holds enough drug to deworm a single 1,250-pound animal. A 79-year-old man bought a tube online after his primary care doctor refused to prescribe ivermectin, swallowed it, and ended up needing two operations.
The paste congealed into a firm mass about 4 centimeters across that blocked his small intestine. After surgeons removed it, he began bleeding, needed three units of blood, and went back to the operating room, where more than 50 centimeters of ulcerated small bowel was removed.
