A US trainer has been suspended for 18 months after two of his horses tested positive for Viagra at Del Mar last year.
Mike Mudaris was also fined $US17,500 after a ruling by the California Horse Racing Board, which was released on Monday.
The horses in question finished fifth in races at Del Mar in August 2016 before both tested positive for the drug, which is also known by its scientific name sildenafil.
Veterinary studies have suggested sildenafil could be used as a measure to prevent or lessen the severity of exercise induced pulmonary haemorrhage in racehorses.
Mudaris's lawyer Roger Diamond told the Daily Racing Form that the trainer did not administer the drug to the horses but was convicted under similar rules to Australia that state the trainer is primarily held responsible for positive swabs.
Diamond said Mudaris has lodged an appeal against the penalties.
"He wants to correct the record," Diamond said.
"The board of stewards did not find Mudaris put any Viagra in the horses' food or drink. It was allegedly done by his employees. He was not there at Del Mar that day.
"It was a mitigating factor. He didn't deliberately do it."
A New Mexico quarterhorse trainer was suspended for 16 years for a similar offence in 2014.
