CANNABIS
& DRIVING.

Cannabis and Driving - Kenny Tynan

 

Big changes to Ireland happened in 2016. TD Gino Kenny’s Cannabis for Medicinal Use Regulation Bill 2016, after passing through all stages, was tabled due to a government money message. In response to this the Government promised to set up a Medical Cannabis Access Program (MCAP) under the independent body HIQA’s guidance. Until this program was set up, patients would be allowed to gain access to medicinal cannabis products in Canada or Holland, by ministerial licence. To this day, there have been 50 licences granted, and the MCAP has not started. Recreational use, although common amongst adults of all ages, remains illegal, therefore an illicit black market still remains. Along with the stigma cannabis carries, there is very little information available to the public about it’s risks and benefits.

 

In Ireland, many people drive from rural areas, villages and towns to bigger cities like Galway, Dublin and Cork for employment. A car is essential for food and visiting loved ones and family for people who live in rural areas where public transport is not available. Ireland is an island with beautiful beaches and scenery, so internal as well as external tourism is a big factor on the roads.

 

In Ireland, it is not uncommon for heavy users to consume cannabis while driving, or just before. Many other consumers will have residual effects of THC and continue to drive. Driving under the influence of any drugs has been illegal in Ireland since 1961, with a zero tolerance approach. In 2017, Garda were given the power to conduct roadside drug testing, and the previous requirement to prove impairment no longer applied.

 

Different methods of consumption and duration of cannabinoid presence in the blood, can potentially impact driving. Cannabis is the second most common substance found in road fatalities in one study in Canada, however it was found that it was also mixed with alcohol in many cases. Driving simulator studies have all shown impairment in driving, especially in high doses of cannabis. These include difficulty keeping in lane, increased response times to light changes, and increased likelihood of collision with unforeseen complications while driving.

 

Smoking is the most common way of consumption in Ireland, as it provides the fastest “high” due to the delivery time between the lungs and the brain. Many factors contribute to the bioavailability when consumed in this way, such as the concentration of thc in the cannabis, the amount of puffs, the intervals between each puff, and the length of time it is in the lungs. THC can be found in blood after just one puff. After inhaling cannabis, it reaches its highest peak in concentration in the first few minutes and begins to rapidly reduce within a half hour, and with almost nothing left in the blood after two hours.

 

For most licenced medicinal cannabis patients in Ireland, the method of consumption most common are oils containing THC and CBD. These are administered under the tongue and therefore to take advantage of the oral mucosa where it gets absorbed quickly, although a certain amount will inevitably be swallowed and absorbed in the digestive system, therefore true bioavailability isn’t easily determined.. Peak concentration with sublingual administration occurs with 1 ½ hours and 4 hours, and is gone between 12 and 24 hours.

 

A common way of consumption for non licenced patients in Ireland are edibles, as the only high concentrate medicine they can get on the black market is full extract cannabis oil, usually extracted with alcohol, or in the rare case, ethanol. The taste of this can be quite bitter so a lot of patients choose cannabis edibles, which are absorbed by the alimentary tract. These have a similar onset and peak times as sublingual oils, from peaking within 1 hour to 5 hours and have shown a bioavailability of between 5 and 20%.

 

Since 2017, Garda has powers to stop a vehicle and carry out a roadside test for cannabis without proving impairment. An oral fluid test using a device called the Drager Drug Test 5000 is used to track the presence of cannabis, benzos, amphetamines, opiates and cocaine. If a person tests positive, they are then taken to a local Garda station, where a blood sample will be taken to determine the concentration of cannabis in the blood. Under current laws, a person has to test 1ng/ml THC or 5ng/ml THC-COOH, which is not water soluble, so it stays longer in the blood. People who consume cannabis regularly may still test positive weeks after they have stopped using cannabis.

 

Considering these facts, it is not possible to determine impairment, when cannabis was last used or the quantity consumed - with the roadside test, or testing plasma.