On April 3, the Canadian Pari-Mutuel Agency released an updated medication elimination guideline for the use of Ventipulmin (the brand name for clenbuterol). Under the new guideline, Ventipulmin would be prohibited 28 days prior to race day with new testing set to begin on May 1, 2020.

This revised withdrawal time is a three-week increase over the CPMA’s previous requirement of seven days and is double the model rule of 14 days recommended by Racing Commissioners International (RCI).

Currently, California has the strictest clenbuterol regulations among thoroughbred racing jurisdictions. There, the withdrawal time is 30 days. Ventipulmin is already banned in Quarter Horse racing.

Critics and Advocates

The CPMA’s announcement comes as a welcome policy shift for some in Canadian horse racing. Canadian Hall of Fame trainer Mark Casse has been highly critical of clenbuterol misuse in thoroughbred racing and calls the new guidelines a smart move.

“I think Canada is staying ahead of the game in terms of what is coming,” says Casse. “I think you are going to see crackdowns in the US because the image of the industry is at stake, especially after what happened at Belmont.” (Back in March of this year, 27 people including trainers, veterinarians and drug suppliers were arrested in a wide-ranging doping scheme. One the drugs confiscated in large quantities was clenbuterol.)

“The horses suffer,” Casse says. “There is so much abuse of this drug and the effects it has on bone density and damage to the heart that the negatives outweigh the benefits of having the drug available.”

Clenbuterol also has similar properties to anabolic steroids despite not being a steroid.

Not everyone agrees. Veteran owner and trainer Glen Todd believes fear about the misuse of clenbuterol is overblown.

“The way the industry is moving, the new rule makes sense,” says Todd, “but I don’t think the drug is abused as much now as it used to be.

“I think seven days out was a good rule. Now, it’s going to be difficult to treat pure bleeders because Ventipulmin is best for pure bleeders. Since 78% of horses bleed, we’ve got a problem.

“If eight of 10 horses couldn’t run, the industry would be in trouble.”

Brian Tropea, general manager of the Ontario Harness Horseman Association, agrees with Todd, arguing the new guideline will essentially eliminate the legitimate therapeutic use of clenbuterol.

“The rationale behind the change is to stop the misuse of the drug,” Tropea says. “Standardbreds race every week, which means we can’t use it. So now the most effective drug for horses with breathing difficulties is out of reach.”

According to Tropea, the United States Trotting Association is launching a petition against the RCI’s 14-day recommendation. There is no word as to whether Canada’s harness racing industry is planning similar action against the CPMA’s new extended timeline.

A Double-Edged Sword

Clenbuterol is a bronchodilator that belongs to a class of drugs known as beta-2 agonists. These drugs work by replicating the functions of catecholamines ‒ hormones such as epinephrine (adrenalin), norepinephrine, and dopamine that are made by the adrenal glands. Beta-2 agonists “imitate” catecholamines so that when taken orally or inhaled, they relax the smooth muscle in the airways which allows air to flow in and out of the lungs more easily for a limited time.

The problem with clenbuterol is two-fold. On one hand, it is a useful pharmaceutical. Veterinary sources say clenbuterol is the most effective therapeutic treatment for viral respiratory infections in horses. Recovery time with the drug can be shortened from 21 to 14 days and the ease of administration has not been duplicated with any other respiratory drug.

On the other hand, clenbuterol may have potential anabolic side-effects when given for prolonged periods of time or at higher-than-normal doses.

Inhaled short-acting bronchodilators such as Ventolin can be administered using inhalation device/nebulizer such as this Flexineb Inhaler.

Some beta-2 agonists like Ventolin (salbutamol) are short-acting and usually remain in the body for 24 hours or less. Clenbuterol is long-lasting and can remain in the body for 30 days. Moreover, unlike other beta-2 agonists like salbutamol, clenbuterol may mimic the effects of anabolic steroids.

In scientific studies of rats, clenbuterol has been proven to increase the conversion of fat deposits into lean muscle and promote an upsurge in muscle mass in response to physical exertion. The drug is widely used in the livestock industry for the production of lean tissue in meat.

Anecdotal evidence from human athletes and body-builders who have illegally used the drug indicates that continued use of clenbuterol at levels exceeding manufacture recommendations can lead to brittle bones, muscle tearing, cardio-vascular problems and myocardial infarction. The drug is not approved for human use in Canada or the US.

To date, there are no scientific studies supporting claims that clenbuterol can have a performance-enhancing effect in horses but, as Casse maintains, horsemen wouldn’t be so willing to misuse the drug if it didn’t give them an edge.