Aprotinin, known also as Trasylol by its manufacturer Bayer, is an intravenously administered medication used to reduce bleeding during complex surgical procedures, mainly in heart and liver surgeries.  The major benefit of the drug during such delicate surgeries is the slowing down of fibrinolysis the process that leads to the breakdown of blood clots. It decreases the need for blood transfusions during surgery, as well as preventing major organ damage by preventing a drop in blood pressure. 

While Aprotinin was available as early as the 1960s, it did not see wide usage in its most recent capacity until it was picked up, patented, and aggressively marketed by the Bayer Corporation as Trasylol towards the end of the 1980s.  Its initial promise lay in its ability to inhibit pancreatic enzymes and its earliest use was in the treatment for acute pancreatitis, in which destruction of the gland by its own enzymes is thought to be part of the pathogenesis.  However, it did not see any use in major surgeries where blood loss was a concern until the late 1960s. 

Bayer began funneling serious capital into the research and development of Aprotinin as a replacement medicine for aminocaproic acid, the most commonly used anti-fibrinolytic medication given to control post-operative bleeding.  Routinely, patients undergoing major surgeries involving potential blood transfusions, sustained bleeding, or large amounts of blood loss have been given aminocaproic acid, with a relatively low rate of drug-induced mortality.  In fact, the largest risk factor for patients receiving aminocaproic acid was not due directly to the drug's interaction with the patient, but rather from acute thrombosis, the formation of a clot inside a blood vessel obstructing the flow.  This can have several potentially fatal results; kidney failure, heart attack, or stroke are all possible outcomes of this Trasylol side effect.  However, as with any major surgery, these are calculated risks, almost precisely dialed down to an exact percentage.  In many cases, the likelihood of a healthy patient fatality in major surgery is less than 5 percent.  Indeed, this is due not only to the advances in medical technology, but also to the knowledge, research, and practical application of tested medicines. 

This was not the case for Trasylol; through dubious politics, aggressive marketing, and generally questionable events surrounding it's takeover of the market, Trasylol became the medical industry standard for open heart and liver surgeries.  This meant huge profits for Bayer; sales of the drug hit $300 million in 2005, with projected sales of $750 million for 2006.  It was the flagship drug and had all but monopolized the anti-fibrinolytic and anti-proteolytic marketshare.  However, it has recently been discovered that Bayer was aware of an increased Trasylol risk of fatality, almost 64 percent higher,  in patients receiving Trasylol during surgery.  While several studies have recently come out showing the dangers of Trasylol and it's tendency to induce both acute renal (kidney) failure, heart attack, stroke, and death, this is not new knowledge to the Bayer corporation. 

It is now known that as early as the beginning of the 1980s, the concerns over the potentially fatal side effects of Trasylol have been known.  Dr. Juergen Fischer, director of the Institute of Experimental Medicine at the University of Cologne, found severe kidney damage in animals given Trasylol. When he relayed the results of his research to Bayer, they disregarded the information, overlooking a potentially deadly Trayslol side effect.  Soon thereafter, similar side effects showed up in patients given the drug in US hospitals.  Nor is this an isolated event.  Concerned over the abnormally high mortality rate in patients receiving Trasylol, the Canadian government commissioned a study to test the hypothesis that Trayslol was superior to other drugs in decreasing bleeding during cardiac surgery.  Shortly after the study began, that study was halted because Trasylol appeared to increase the
risk for death compared with two other drugs.  Under pressure from the FDA and the Canadian government, Bayer put a temporary moratorium on marketing for this deadly drug. 

It is believed that approximately 4.5 million people have been given Trayslol worldwide; a third of those patients, about 1.5 million people, were given the drug in the United States in the 14 years the drug was available.  By some estimates, in the brief time frame between several damning studies and the most recent temporary stop on the drug, if the drug had been taken off the market, it could have saved about 22,000 lives - approximately 1,000 people every month.