An Aussie veterinary surgeon has been struck off the register after admitting she injected two friends with a horse tranquilliser during a boozy, drug-fuelled weekend south of Perth. 

Catherine McGuigan has long worked at Murray Veterinary Services in Coolup, but in a recent State Administrative Tribunal (SAT) ruling she was found guilty of unprofessional conduct. 

The SAT said McGuigan began socialising with a couple who used her services and "from time to time, [they] took trips away together during which they used illicit drugs, including ecstasy and cocaine for recreational purposes". 

During a weekend in October last year, the trio stayed at an apartment in Wannanup and were drinking and consuming cocaine when McGuigan grabbed a 100ml bottle of ketamine from her car. 

She then asked her female friend how much she weighed so she could "check on the internet the correct dose of ketamine to administer". 

McGuigan also gave ketamine to her male friend and for herself. 

"When acting in the lawful practice of her profession as a veterinary surgeon, the respondent was authorised to possess ketamine but was not authorised to administer or use ketamine on humans," the SAT said. 

McGuigan told the couple she could lose her job for giving them the drug and made them promise to keep the secret. 

About one month later, McGuigan gave the same woman diazepam to help her sleep. 

"The respondent was required to make a clinical record of its supply but she did not do so," the SAT said. 

Late last year, McGuigan gave herself Airway Gel, which is a broncho-dilating agent for horses and also contains clenbuterol hydrochloride. 

"The respondent misused, or improperly used, the authority granted to her as a registered veterinary surgeon," the SAT said. 

"As a veterinary surgeon, she was only authorised to administer, supply or use ketamine, diazepam and clenbuterol hydrochloride for the treatment of an animal." 

The tribunal further added that McGuigan's actions "would reasonably be regarded as disgraceful or dishonourable by registered veterinary surgeons of good repute and competency". 

But they accepted McGuigan was remorseful and had accepted responsibility for her actions. 

She was fined AU$1000 ($1039), plus AU$3000 in costs, and was removed from the register of veterinary surgeons in WA. 

- Angie Raphael, news.com.au