Is it safe to drive while taking medicinal cannabis (& CBD Oil)?

One of the many queries patients have when initiating a medical cannabis treatment is, can I still drive? Unfortunately, federal law says it is illegal to drive with any amount of the main intoxicating cannabinoid, THC, in your system. Yet that may soon change – in one Australian state at least.

Current laws for driving with a medical cannabis prescription

At present across Australia, it is illegal to drive with the presence of THC in your system. There are currently no exemptions for individuals taking prescribed medical cannabis.

CBD products make up a large portion of medical cannabis products prescribed. However, even a “CBD-only” formulation may have a tiny and undetectable trace of THC. And even high CBD/low THC formulations can result in detectable saliva and blood levels of THC, thus making it prohibited to drive. Therefore, the dilemma lies in the fact that current Australian legislation says that you must have no trace of THC.

Roadside tests don’t differentiate

Medical or illegal, impaired or capable – roadside tests only test for the presence of THC. Whether or not it has been prescribed medically or illegally ingested cannot be determined by a simple saliva swab.

Roadside drug swabs can detect THC levels in an individual anywhere between 24 hours to 30 days after ingestion. Unlike blood alcohol levels, THC present in saliva or blood is not a definitive marker for cognitive impairment, nor can blood levels be extrapolated back in time like blood alcohol concentrations.

Prolonged presence of THC in the system is due to it being stored in fat tissue of long term cannabis users or medical cannabis patients. This can pose a serious problem for those needing to drive that take daily doses of medical cannabis over extended periods.

Other than medical cannabis, there is no other prescription medication where it is illegal to drive with even the presence of the medicine in your system.

This follows old patterns of stigmatisation against cannabis as a recreational drug, in reality ingesting medicinal cannabis products is much different from taking illegal cannabis. Given the growing number of medical cannabis patients in Australia, cohesive and country-wide reforms need to be made.

Medical cannabis reform continues: driving laws set to change in Victoria

Medical cannabis patients and proponents such as Reason Party MP Fiona Patten believe that medical cannabis should be regulated just like any other prescribed medicine, where guidelines are provided and patients are assessed for their capacity to drive.

Together with many other voices, Fiona Pattern has put forward a bill to allow medical cannabis patients to drive if unimpaired. This will align medical cannabis with all other prescriptions medicines that have the potential to impact driving ability.

The Road Safety amendment is on track to be approved for early 2021, which will make Victoria the first state to remove legal barriers for medical cannabis patients to drive.

Research into cannabis and driving

Recently released research by the Lambert Initiative for Cannabinoid Therapeutics at the University of Sydney showed that CBD dominant medications did not cause cognitive or psychomotor impairment when driving.

“These results provide much-needed insights into the magnitude and duration of impairment caused by different types of cannabis and can help to guide road-safety policy not just in Australia but around the world.”

Dr Thomas Arkell, The Lambert Initiative

The study confirms what we know from other research, that THC has the capacity to impact driving and confidence in driving, and CBD does not likely impair driving abilities.

Regardless of the limited studies conducted on the effects of cannabis on driving, the consensus is THC does diminish individuals’ ability to drive safely. Impairment is thought to peak around 30 minutes to one hour after inhaled cannabis and continue for 3-5 hours.

Driving appears to be impaired in a dose-dependent manner and the degree of THC intoxication can vary greatly between individuals. Most research pertains to inhaled cannabis, so there may be differences in terms of other administrations like oils, sprays or others.

The road ahead

Cohesive laws across all states that provide exemptions for medical cannabis patients to have THC in their system will be necessary moving forward, and Victoria’s example may prompt other states to make progress on this matter.

Workable options proposed range from treating drivers on medicinal cannabis no differently from how they would currently test for impairment on other drugs, or developing roadside impairment tests to be applied for any prescription drug.

In the meantime, those with medical cannabis prescriptions should discuss with their prescribing doctor.

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