Over-the-counter medicinal cannabis plan not what it seems, experts warn

Medicinal cannabis could be available over-the-counter in Australia by next year as the national medicines regulator weighs a proposal to allow it to be sold without a prescription, but some experts warn the approach could backfire.

New research published in the International Journal of Drug Policy suggests the Therapeutic Goods Administration's plan to allow chemists to sell a month's worth of cannabidiol at a maximum dose of 60mg per day is unlikely to benefit patients - who were likely to "self medicate" instead.

The paper's co-author Professor Iain McGregor, academic director of Sydney University's Lambert Initiative for Cannabinoid Therapeutics, said much higher doses were needed to give relief to patients with chronic pain, insomnia, anxiety and epilepsy.

"There is no good quality evidence that 60mg does anything useful," Professor McGregor said.

The TGA last week released an interim decision to amend the Poisons Standard to allow cannabidiol to be sold over the counter at the restricted dose to adults, inviting public comment until October 13 with a final decision due in late November and implementation in February.

Professor McGregor warned that without appropriate dosing, thousands of such patients may instead continue "self medicating" with illicit use of cannabis, which unlike cannabidiol products contains tetrahydrocannabinol (THC) - the psychoactive compound that gets users high.

Whether they smoked cannabis or bought cannabidiol products on the black market, he said, "these people may just bypass the medical profession."

There was "very good evidence" in scientific research that 300 to 400mg of cannabidiol was effective at treating anxiety, he said, and "reasonable" evidence that this dose could effectively treat insomnia and chronic pain.

Cannabidiol (CBD) is a non-intoxicating component of the hemp plant. Currently, patients who want to use CBD products have to find a doctor who is familiar with the process of applying through the TGA's special access scheme to legally prescribe them.

About 10,000 Australians adults were accessing the drug through this channel, Professor McGregor said, while an estimated 600,000 "may be self-medicating a medical condition with cannabis."

While some patients might purposely exceed the 60mg dose, he said, this would mean a pack would only last four to five days and the other ingredients may cause side effects.

Greens Senator Rachel Siewert said cannabis was "a unique product that needs unique independent regulation", calling for a new body to be established to regulate medicinal cannabis products outside of the TGA.

"If ineffective doses are supplied to consumers, it will diminish confidence in the product," Senator Siewert said.

The report of a Senate inquiry into barriers to patient access to medicinal cannabis in Australia in March found that allowing those products containing low-dose cannabidiol with "very low levels" of psychoactive compounds to be sold over-the-counter "would greatly increase the accessibility of these products for patients."

"It would also bring Australia closer in line with models of access in countries such as the United Kingdom and Canada," the report said.

The World Health Organisation's expert committee on drug dependence recommended in 2018 that pure cannabidiol (CBD) products not be placed under international drug control "as the substance was not found to have psychoactive properties, and presents no potential for abuse or dependence."