The New Mexico Racing Commission has suspended the use of clenbuterol for Thoroughbred and Quarter Horse racing, effective April 20, 2012. The suspension, passed by the commission Feb. 23, will be in effect for 12 months at all tracks in New Mexico.

Clenbuterol is a bronchodilator, and it is used in horses with respiratory problems to relax smooth muscles in the airway, causing the airway to dilate. It also stimulates the activity of the cilia in the trachea, assisting the process of eliminating mucus and microscopic debris. Clenbuterol is a β2 agonist and like all drugs in this category has adrenergic (muscle building) effects, especially at higher dosages. In some cases, clenbuterol is used as a replacement for banned anabolic steroids, which poses serious health risks for the horse.

"This is a great step forward for racing in New Mexico and throughout the United States," said Ruidoso Downs general manager Shaun Hubbard. "This is a big step to enhance the integrity of racing and is, simply, doing what is best for the horse."

Ruidoso Downs, located in Ruidoso Downs, N.M., which aggressively pushed the clenbuterol measure, begins it summer seasons May 25. It runs through Labor Day