Drug-driving campaigners and cannabinoid researchers have used a NSW parliamentary inquiry into Greens MP Cate Faehrmann’s medicinal cannabis exemption bill to make the case for change.

If passed, The Road Transport Amendment (Medicinal Cannabis — Exemptions from Offences) Bill 2021 would provide a defence for medicinal cannabis users against drug-driving charges. 

NSW Greens MP Cate Faehrmann

Currently, patients in NSW risk criminal penalties if THC is detected in their saliva during a roadside drug test, regardless of impairment. The rules do not apply to users of other prescription drugs.

Lambert Initiative academic director Professor Iain McGregor told the inquiry the increase in medicinal cannabis prescriptions in Australia since legalisation in 2016 had seen it become a “mainstream medicine”, but that restrictions around driving were making it hard to sign up patients for trials.

McGregor pointed out that cancer symptoms were among the top 10 conditions for which medicinal cannabis was prescribed, but that persuading people undergoing chemotherapy to participate in a study was difficult when they would be unable to drive.

“These patients were told, ‘sorry you’re not allowed to drive for the duration of several weeks of that trial’. We estimate about 50% of potential recruits to the trial walked away for that reason.”

He added the problem was “particularly acute” in regional areas where people were reliant on their cars.

Former magistrate and Drive Change campaigner David Heilpern said the laws had been introduced before the advent of medicinal cannabis and that the sensitivity of the tests added to their unfairness.

Swinburne University of Technology research fellow Dr Thomas Arkell told the inquiry it was very hard to gauge how long THC stays in a driver’s system.

He said: “In oral fluid, which is obviously what roadside drug testing uses, it’s highly variable. For a lot of people, it can be gone within a couple of hours.”

Arkell cited a study in Victoria where “some people are still testing positive the following morning for somewhere between 10 and 12 hours after they would have last used a dose of whatever product they’ve been prescribed”.

He said it was possible for THC to be present in a driver’s oral fluid and for them not to be impaired at all.

Lambert Initiative
Professor Iain McGregor from the Lambert Initiative

“It may be for some people that it does reflect recent drug use and impairment. But it’s not a reliable indicator,” he added.

“The real comparison we should be making is to other medicines that patients already do take and drive under the influence of. We should treat all medicine equally.”

Lambert’s Dr Danielle McCartney cited its analysis which identified a ‘window of impairment’ of between three and 10 hours caused by moderate to high doses of THC.

She said five hours was the general recommendation to wait before driving after medicinal cannabis use, adding some patients may consume “lower doses of THC to avoid intoxication”.

McGregor said studies showed an increased crash risk of 10 to 40% for those “acutely intoxicated with cannabis”, but said no quality studies had been conducted examining medicinal cannabis users and driving.

“Our assumption would be the crash risk may indeed be minimal, if not negligible, in people using cannabis for medical reasons,” he said.

“If you’re alleviating a medical condition, be it insomnia, pain or spasticity if you have MS, these are conditions that will impair your driving anyway. If you’re taking medication that relieves your pain, insomnia and spasticity, then that may actually improve your driving.”

In its submission — one of 105 to the inquiry — The Law Society of NSW said the government had provided a medical defence for those using morphine to manage pain, adding “we consider it appropriate to provide the same defence for those who legally use medicinal cannabis”. 

Faehrmann agreed: “Medicinal cannabis is far safer than morphine and other opioids on and off the road, but it’s only medicinal cannabis patients who test positive who face life-destroying drug-driving charges,” she said.

The Perrottet government has said it will not be supporting the bill and submitted a statement to the inquiry arguing “medicinal cannabis is not comparable to other drugs, in part due to its widespread use and availability for non-medicinal purposes”.

“There is no reliable way to distinguish or prove whether the source of THC is illicit or prescribed,” it added.

The bill is likely to need support from the opposition Labor party to pass.

Prior to launching Cannabiz, Martin was co-founder and CEO of Asia-Pac’s leading B2B media and marketing information brand Mumbrella, overseeing its sale to Diversified Communications in 2017. A journalist...