Adelaide Cancer Centre oncologist Brian Stein said he had abandoned an attempt to complete the application process to provide the drug on a one-off basis and bemoaned the “arduous” process.

Dr Stein said a shortage of data about how much of the drug should be used to treat different conditions and an inability to know exactly what doctors are prescribing were the main issues to overcome before he was comfortable prescribing medicinal cannabis.

Dr Stein said he was approached by a cancer patient who was “very keen” to get a prescription to use medicinal cannabis, but she died before he completed the paperwork.

If accredited under Special Access Scheme B, Dr Stein would have become South Australia’s second medical professional permitted to provide medicinal cannabis to a single patient.

There are no South Australian “approved prescribers” of medicinal cannabis — medical professionals who are able to supply the drug to patients on a general basis.

Dr Stein stressed he had no designs on becoming the state’s first authorised prescriber: “I’m not interested in becoming Mr Medicinal Marijuana, but I will consider individual patient requests”.

To prescribe cannabis in South Australia, a doctor must obtain the approval of the Therapeutic Goods Administration, as well as the state Drugs of Dependence Unit.

Dr Stein said he had a “number of substantive issues” with DDU’s application process.

“The unit want you to prove the drug you’re prescribing does something useful and the scientific evidence on medicinal marijuana is not particularly strong,” he said.

“I don’t have a book that says if you have nausea, then you should take this much of this particular strain of the drug. If you look at it as a scientist, one of the biggest issues with medicinal marijuana is what are we prescribing?

An indoor nursery for growing medical marijuana. Photo: istock

“It’s not me saying ‘I don’t believe this could be useful’, but I need evidence to make regulators happy and evidence to make me happy that one patient will get the same stuff as the patient that came before them.”

Greens MLC Tammy Franks said Dr Stein’s comments bolstered the case for controlled growing and testing of medicinal cannabis.

“Doctors need to be given some guarantees about what they’re prescribing. They’re also given no protections and given no support and training,” she said.

A spokesman for Federal Health Minister Greg Hunt said a medical practitioner could receive TGA approval to provide cannabis within four days by filling out a one-page Special Access Scheme B form.

“States and territories have their own legislation around access to medicinal cannabis, including what type of practitioner can prescribe,” the spokesman said.

“Creating a more consistent approach to patient access to medicinal cannabis is something the minister raised at COAG Health Council last week.”