OK, anybody who knows me knows I can’t possibly let the lasix study go by without giving my opinion on it. For those of you who haven’t seen it, a bunch of American veterinarians decided to actually do a real study on whether or not Lasix actually reduces bleeding in racehorses. Americans have been pumping their horses full of the stuff for the past 30 years or so based on purely anecdotal evidence that it has any effect on the problem. So now, finally, there is a study. Here’s the bad news: Guess what, it seems to actually reduce the incidence of bleeding, giving ammunition to those who justify its use and think racing can’t possibly live without it.
But before you all jump on the “I told you so” bandwagen and call the rest of the world barbarians for not using it, let me point out there are some very important factors in this study that need to be considered. First, and most importantly, the study did not investigate any detrimental side effects that might be associated with repeated use of lasix. Secondly, researchers admitted they still had no idea HOW the administration of lasix actually reduced bleeding; the drug also acts as a bronchodialator, which means it might be possible that it simply reduces the flow of blood to the area seen when scoping a horse after the race.
All thoroughbreds bleed a bit in the lungs during a race or strenuous workout. (Humans do, too; that’s why you end up having a coughing fit if you run too fast when out of shape.) Most of this bleeding is benign, and can be managed by having a horse fit and ready to do the job at hand. Exterior factors like pollutants and temperature can play a roll, but managing stress and maximum fitness are the most important factors for limiting damaging bleeding. The study, conducted in South Africa by Colorado State University, classified the severity of bleeding between zero and 4, with 4 considered a severe bleeding episode. It found that 80 percent of the horses given a saline solution showed evidence of bleeding, while 55 percent of the horses given Lasix showed bleeding. So yes, while the incidence was reduced, HALF THE HORSES GIVEN LASIX STILL BLED. The study also showed that Lasix was most effective in limiting severe bleeding; none of the horses in the study given the drug had a Level 4 bleeding episode, but 10 percent of the saline control group did.
The study said it considered the conditions of horses trained in South Africa to be pretty much the same has horses trained anywhere else in the world. “Although racing and training conditions in other parts of the world do differ from those in South Africa in minor respects, we do not have any evidence that any of these differences
have been demonstrated to have an impact on the frequency or severity of EIPH,” or exercised-induced pulmonary hemorrhaging, the study said. I’ve never been to South Africa, but I have observed horses in training in England, Ireland, the United States, Dubai, Hong Kong, France and Germany, and I can tell you that there are HUGE differences in the way horses in these countries are trained. Considering how susceptible the modern thoroughbred is to the smallest differences in environment, I cannot imagine how the difference in conditions would not make a difference on bleeding during a race.
The study notes that 92 percent of horses in North America are treated with Lasix, making it a $100 million a year market. It concludes that the drug is really most effective only with severe bleeders. Surely, 92 percent of North American horses can’t possibly fall into this category. If so, there are problems with thoroughbreds far greater than Lasix can help. Oh, and by the way, horses treated with Lasix lose THREE TIMES MORE WEIGHT during a race than a horse not treated with Lasix. So is this really the most humane way to race? Let’s hope racing officials around the world don’t buy into Lasix – or at the very least, let’s see some more study as to how it really works, and what the detrimental effects might be. Race day for horses around the world should not start with a syringe.