The bronchodilator clenbuterol, possibly being misused for its anabolic steroid properties, will be severely curtailed for the next year at all California racetracks.

The California Horse Racing Board (CHRB), meeting at Betfair Hollywood Park May 24, approved a 21-day withdrawal period from the commonly used drug for any horse entered in a race. The move, which becomes effective with the start of the Del Mar summer meet July 18, will be in effect for one year.

The delay in instituting the change will give horsemen a chance to adjust their medication regimen. The previous withdrawal period for clenbuterol was 96 hours.

The board took the unanimous action under its emergency power rule, which allows it to circumvent the full rule-making process that would have required a 45-day public comment period. It could institute a permanent rule change at a later date