South Australia's deputy coroner has called for better mental health support for veterinarians as repeated calls to better secure a drug linked to almost 20 suicides per year continue to be ignored.

Key points: Veterinarian Amy Patterson and student Erin Murray used the drug to end their lives.

Veterinarian Amy Patterson and student Erin Murray used the drug to end their lives. An inquest found it was "incomprehensible" tighter regulations on the drug had not been imposed

An inquest found it was "incomprehensible" tighter regulations on the drug had not been imposed The inquest found the veterinary industry needs to acknowledge the "high levels of stress" it can cause

Anthony Schapel investigated the deaths of Erin Paige Murray, 25, and Amy Jean Patterson, 30, who used the veterinary drug to end their lives in 2014 and 2015 respectively.

Ms Patterson was a qualified veterinarian at the time of her death and Ms Murray was a veterinary science student who had completed work experience in the weeks before she died.

The inquest heard the national regulator — the Therapeutic Goods Administration (TGA) — previously refused to mandate that the drug be better secured within vet clinics because it would cost too much.

A similar inquest into the death of a dog groomer in Queensland in 2017 found that the drug should be upscheduled from "Schedule 4" to "Schedule 8" in the Commonwealth Poisons Standard, which would require it to be more securely stored and monitored in vet practices.

In his findings, Mr Schapel repeated the Queensland coroner's calls and said it was "difficult to understand" why the recommendation had not been implemented.

"A failure to store [the drug] in anything other than a locked container when not in use is utterly incomprehensible," he said.

The inquest heard the TGA had previously objected to upscheduling the drug — which the ABC has chosen not to name — because there was "the potential for animal welfare to be compromised if the substance did not have easy access".

It also objected on the basis that it would be "onerous for veterinarians" because they would have to pay for larger safes to store the drug.

However, the TGA noted that implementing better storage arrangements for the drug would not necessarily require its upscheduling.

In an email to the ABC on Wednesday, it provided a link to its decision in 2017 to not change the drug's schedule following the Queensland coroner's recommendation, without commenting further.

"The delegates' final decision is that the current scheduling for [the drug] remains appropriate and that state and territory governments consider standardisation of the controls under their legislation," the chemicals and medicines scheduling committee decided.

Drug connected to 18 suicide deaths per year

According to the Veterinary Surgeons Board of South Australia (VSBSA), there have been 18 suicides in the industry per year, through use of the drug, since July 2000.

In his findings, Mr Schapel acknowledged that the incidence of suicide within the veterinary profession is greater than within the general community.

"In my opinion the arguments that favour a mandatory requirement that [the drug] be kept in a locked container or safe except when in use, and even when in transportation, are powerful ones and that they outweigh the totality of argument to the contrary," he said.

Deputy state coroner Anthony Schapel investigated two deaths linked to the same veterinary drug.

VSBSA presiding member John Strachan gave evidence at the inquest.

He said the board supported upscheduling the drug and that installing appropriate safes would only cost veterinary practices about $500.

The inquest heard the VSBSA wanted to regulate the storage of the drug but under current legislation, it only had power over veterinary hospitals, not veterinary clinics, which are categorised differently under legislation.

The majority of veterinary practices in South Australia are categorised as clinics.

Mr Schapel recommended that the Veterinary Practice Act be amended to give the VSBSA jurisdiction over all veterinary practices.

Preventing vet suicides requires 'holistic solution'

However, Mr Schapel said he was mindful of the fact that keeping the drug in a locked container may not prevent all suicides through its use.

"Some veterinary surgeons will need and have routine access to the substance even if it is under lock and key," Mr Schapel said.

"But it seems to me that persons who work in veterinary practices who would not conceivably need to use and have access to the substance — such as some nurses, students, groomers, administrative staff and other employees — will be better protected if the substance is housed in a locked container."

Mr Schapel said preventing suicide deaths in the veterinary profession required a "holistic solution".

"It should be noted that pressing issues in the profession include high levels of stress and long hours," he said.

"There is a need for the development of mentoring programs and mental health programs for members of that profession."

Adelaide vet Andrew Spanner does his best to limit access to the drug. ( ABC News: Claire Campbell )

No way to full prevent access: vet

Adelaide vet Dr Andrew Spanner said most veterinary practices did lock up these drugs as recommended by the VSBSA.

"We can't completely exclude access but we try to limit it as much as possible," he said.

"Our main issue with that directive is it's unlikely to fix the problem because we still need access to the drug on a regular basis. It's going to be very hard to ever stop people accessing it opportunistically when we have it out for other purposes."

He said the coroner's recommendation for mental health and mentoring programs for vets, veterinary nurses and veterinary students was a "fantastic" idea.

"We certainly have a high-pressure environment, we have a situation where vets often work in a fairly isolated way and don't have good support from other vets," he said.