USA — Bayer announced in November 2007 that it was halting worldwide sales of Trasylol, a blood clotting agent used in heart surgeries. Already under intense scrutiny, Trasylol was pulled after an Ottawa-based clinical trial was abruptly stopped when researchers found that Trasylol could be linked to a higher risk of death than similar, cheaper drugs made for the same purpose.

Known generically as aprotinin, Trasylol was used to prevent excessive bleeding during open-heart surgery. Introduced in 1993, it has come increasingly under the microscope since January of last year when safety concerns indicated it increased the risk for heart attack, kidney complications and stroke.