Cannabinoids can affect your fitness to drive by impairing your thinking and movement. This factsheet provides some guidance for patients prescribed cannabinoid medications.
Cannabidiol (CBD) is a non-psychoactive cannabinoid and has the potential to cause drowsiness, fatigue, and lower blood pressure. These symptoms are usually observed when taken with other medications that interact with CBD, or with high doses (1500 mg/day).
CBD is known to affect the metabolism of certain drugs that are metabolised by the same enzymes in the liver as CBD and can potentially increase the sedating effects of drugs like benzodiazepines (eg Valium, Xanax).
CBD isolate medicines contain CBD molecules only. CBD isolate contains NO THC.
CBD full spectrum medicines contain at least 98% CBD molecules, and the remaining up to 2%, or less, contains approximately 140 other molecules, one of which is THC. The amount of THC in CBD full spectrum is usually around 1% of the amount of CBD.
Δ9-tetrahydrocannabinol (THC) is a psychoactive cannabinoid and can affect the skills required for safe driving, including: attention, judgement, memory and coordination. Unlike alcohol, a direct relationship between blood levels of THC and driving impairment has not yet been established.
The likelihood of impairment is greatest during initiation of treatment, especially following dose increases and in the hours after administration of a dose.
Patients are advised not to drive or to perform hazardous tasks, such as operating heavy machinery while taking medicines containing THC.
The rate that cannabinoids are metabolised and excreted varies depending on a number of factors including volume of fat tissue, length of treatment and your genetics. This means that some patients could still have THC in their bloods for days or weeks after their last dose.
Roadside drug testing in Australia tests for THC in saliva.
It is an offense in all states and territories in Australia to drive:
- with the presence of THC in oral fluid, blood, or urine (excluding Tasmania);
- under the influence of THC.
There may also be insurance implications for patients convicted of these offenses.