Lasix Is Bad for Horses

With the Lasix ban for juveniles ending with this past weekend’s Breeders’ Cup and a trend toward keeping the drug raceday legal in the U.S., I thought it appropriate to revisit these words written by equine veterinarian Sid Gustafson in The New York Times a couple years back (10/28/11). At the time, Gustafson believed that Lasix was on its way out.

“The only ones who benefit from racehorses being medicated on raceday are the attending veterinarians and, subsequently, the veterinary surgeons. …the science continues to demonstrate that chronic use of raceday drugs degrades the quality and safety of racing while impoverishing the welfare of racehorses. Raceday medications increase the breakdown rate.”

“Lasix begets a plethora of additional drug use. Wherever pre-race Lasix is permitted, additional drugs are administered to most all of the diuretically-infused racing horses by their trainers and attending veterinarians. Lasix allows and encourages a lot of drug use. It legitimized the stage for the medication mentality that has haunted racing in recent years with all the notable breakdowns, sudden deaths and wrecks.”

“Lasix or Salix is furosemide, a potent diuretic that dilutes the urine and lowers the pulmonary blood pressure. The drug alters the electrolyte balance of racing horses and makes them vulnerable to heat stroke and metabolic dysfunction. As well, chronic diuretic use interferes with locomotory abilities required to run biomechanically sound by altering cardiac function, muscle function, nerve function, and most every other physiologic function.”

“Diuretics weaken horses. These days there is little doubt that pharmaceutically weakened horses are more vulnerable to breaking down. It is not surprising that Lasix jurisdictions have more breakdowns than drug-free jurisdictions. We should have known. Now we know.”

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“In two years, American racing jurisdictions are scheduled to join the rest of the racing horse world and eliminate Lasix in the United States and Canada. …Good riddance to Lasix and all the drug use it has encouraged and facilitated. Good riddance to Lasix and all the electrolyte imbalances, metabolic dysfunctions, shortened careers, breakdowns and weaknesses the drug has caused…”

The above is not from some layperson bemoaning racing’s drug culture. Dr. Gustafson is a renowned expert in the field – practitioner, professor, regulatory vet, speaker, and writer – with over 30 years experience. It’s also worth noting that Gustafson is not against horseracing; in fact, he cherishes the “sport.” The facts reviewed: Raceday Lasix is given to virtually all American starters, and it’s bad for horses. Case closed (again).

Previous posts on Lasix:

“Drowning in Their Own Blood”
“Lasix: Cheating, American Style”
“How U.S. Trainers Defend Lasix”

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  1. The facts are laid bare – ONCE AGAIN – by an expert and racing supporter. It is glaringly obvious U.S. trainers and owners have one thing that matters to them and it is their bank accounts. Even owners/trainers that agree Lasix should be banned won’t stand up for the horses’ welfare…”because everyone else is doing it (using Lasix), I cannot lose that edge”. Money vs. horses…money wins every time.

    • You are so right. Lasix is bad for horses and it does not do much, if anything to prevent or even lessen EIPH. Giving it to 2 year olds is even worse because of the depletion of minerals sooo necessary for bone development. Of course 2 year olds should not be anywhere near a race track, but that is an other issue. Giving Lasix to any horse is just plain wrong and giving to these babies is reprehensible, period. What a business !!

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