Evidence ‘not there yet’ – GP

A Marlborough GP says the prescription of medicinal cannabis could be premature.

The Medicinal Cannabis Scheme is expected to be operational at the beginning of next year, enabling the commercial cultivation and manufacture of medicinal cannabis in New Zealand. Medical cannabis company Puro has secured two sites in Marlborough, with plans to start commercial cultivation when the ‘‘law allows’’.

But Renwick Medical Centre GP Dr Buzz Burrell said the science had not caught up with the public debate on the prescription of medicinal cannabis.

‘‘The pure science of cannabis is so in its infancy, it is scary,’’ he said. ‘‘When we are talking about prescribing a product that has not undergone phase-one trialling, we don’t know what we don’t know. It is almost fascinating that we are being asked by society to jump the gun and start prescribing something which has not completed phase-one trials yet.

‘‘We owe it to the public to be as cautious [with medicinal cannabis] as with anything else we prescribe.’’

Burrell said most drugs prescribed to the general public underwent four phases of trials before being released.

He said the Faculty of Pain Medicine (part of the Australian and New Zealand College of Anaesthetists) was also advising doctors not to prescribe medicinal cannabis, as research showed its effects to be ‘‘disappointing’’.

‘‘At the moment the Faculty of Pain Medicine is saying the data is saying don’t do it,’’ he said.

‘‘Chronic persistent pain to a certain degree affects 20 per cent of the adult population.

‘‘If we promise these one in five people that this will alleviate their pain and suffering, that is absolutely cruel.’’

He hoped the Medicinal Cannabis Scheme, which would legislate a licensing regime and standards of quality, would reveal the products were safe to prescribe, particularly for chronic pain.

‘‘It would be wonderful to have a safe product we can prescribe but at the moment I can’t say that with confidence,’’ he said.

Leading New Zealand cannabis prescriber and

‘‘The pure science of cannabis is so in its infancy, it is scary.’’ Dr Buzz Burrell

consultant Dr Graham Gulbransen said patients with chronic pain could not wait around for clinical trials.

‘‘Every day I am seeing desperate patients that are not being helped with standard treatment,’’ said Gulbransen, who has prescribed medicinal cannabis to 1000 patients.

‘‘CBD [cannabidiol] is making life-changing differences in many people’s lives.’’

He said 90 per cent of his patients had reported no sideeffects and the other 10 per cent reported minor things like mouth irritation or drowsiness.

‘‘Medicinal cannabis has a very long history so we know it is safe and it often makes a difference where nothing else will.’’

He hoped law changes in December would allow for more access to information on medicinal cannabis, and for GPS to be able to prescribe a greater range of the product.

Leading New Zealand professor of pharmacology Professor Michelle Glass said there had been two systematic reviews on the use of medicinal cannabis in chronic pain over the past three years.

She said both reviews indicated a ‘‘small effect in a small number of people’’, showing the effects of medicinal cannabis to be slightly more significant than a placebo.

‘‘If you go through all the studies, you find that people report overall feeling better, maybe not so much a reduction in pain,’’ said Glass, who was also a member of the Medical Cannabis Research Collaborative.

‘‘When they are grading the score, the pain is still there, [but] they just don’t care about it as much.’’

More than $1.5 million has been pledged for Puro, which intends to cultivate for research purposes, and then commercially when the Medicinal Cannabis Scheme comes into effect.