Kentucky Derby 2011: Drug use questions hang over US horse racing

Here's what's certain about the Kentucky Derby: The hats in the audience are spectacular, the race takes two minutes, and the purse, topping $2 million this year, is always large. What is becoming less certain in this annual thoroughbred horse race, which takes place Saturday in Louisville, Ky., is its integrity.

The debate, specifically, is over a drug that is routinely injected into competing horses four hours before the announcer at Churchill Downs shouts “they’re off.”

Banned in races everywhere except the United States and Canada, the drug, a diuretic known as Lasix, is meant to mitigate a condition that causes a horse to bleed internally while under extreme physical pressure. But the drug also causes a horse to urinate profusely, lightening its weight by up to 27 pounds and making the animal more nimble in a race. Hence, critics say, Lasix is being used to enhance performance – and to get around rules against using performance-enhancing drugs.

IN PICTURES: Prelude to the Kentucky Derby

The horse racing world’s reliance on Lasix is on the rise, with 95 percent of all US racehorses receiving race-day injections last year, up from 45 percent in 1991, according to a recent Time magazine report.

Such prevalent use is increasing scrutiny of the sport, especially in the wake of a steroid scandal involving trainer Rick Dutrow, whose horse won the Derby in 2008. Last month, Mr. Dutrow was denied a license to race in Kentucky by the state’s horse racing commission. In February, a New York regulatory board suspended Dutrow’s license for 90 days after one of his winning horses was found to have a banned painkiller in its system and hypodermic needles were discovered in his barn.

Use of Lasix on race day presents inherent conflicts, says Kara Rogers, a science writer at Encyclopaedia Britannica in Chicago who specializes pharmacology and toxicology.

“Are we helping the horses because they are being injured [by racing], or is it making the sport unfair by using these drugs? Some of these horses are worth so much money, so using Lasix is prolonging the animal’s career or at least looking out for their health. It’s a difficult argument,” says Ms. Rogers.

High-intensity exercise results in bleeding in a racehorse’s windpipe. When the blood travels to the lungs, it can result in high blood pressure, researchers say. The finding became known in the 1970s, after which Lasix was introduced to the sport to protect racehorses' health.

Just how effectively Lasix diminishes bleeding is a matter of debate among medical experts. Although most agree the drug helps to reduce bleeding, it is common for racehorses using it to experience nose bleeding or other side effects.

“It wasn’t like it cured the problem. It certainly reduced the problem, but it didn’t really cure it,” says Rick Arthur, an expert on horse racing injuries, drug testing, and regulation at the University of California at Davis.

Racehorse fatalities in the US are much higher than in Europe, according to data released this year by the Jockey Club, a British horse racing organization. Over a two-year period that started in November 2008, racehorses at US tracks died at the rate of 1.55 per 1,000 starts on synthetic surfaces and 2.14 on dirt tracks.