One in three people with epilepsy continue to have seizures despite taking anti-seizure medication. Some people may have occasional seizures whilst others may have frequent or severe seizures. This treatment gap has led people to seek other forms of therapy, including medicinal cannabis.
For centuries, the cannabis plant has been considered to have therapeutic benefits including antiseizure effects. Cannabinoids are substances in cannabis that act on cells in the body (called cannabinoid receptors) to cause some effect. Two major ingredients include:
Tetrahydrocannabinol, or THC, which causes the psychoactive effects of a ‘high’.
Cannabidiol, or CBD does not contain mind-altering properties. It has shown some positive effects on certain body systems and may potentially help control seizures. CBD is thought to have an anti-psychoactive effect that controls or moderates the ‘high’ caused by THC, and may even reduce some of the other negative effects that people can experience from THC, such as anxiety.
At this time, The Therapeutic Goods Administration (TGA) suggest the use of medicinal cannabis products should only be considered where conventional treatments have been tried and proven unsuccessful in managing the person’s symptoms.
See this TGA resource for an overview of the guidance for the use of medical cannabis in Australia.
And this TGA resource for guidance in treatment of paediatric and young adults.
CBD may or may not work for you. It is comparable to trying a new medication for your seizures. Sometimes they work, sometimes they don’t. They all have side-effects. We hear different reports and the results vary from person to person.
Bear these points in mind if you are thinking about trying CBD:
There is no certainty it will be effective for your epilepsy or seizure type. It may or may not improve your seizure control. You may have a honeymoon period initially, like any other anti-seizure medication, but there is no guarantee it will work long-term for you.
It has side effects just like any other medication.
It can also affect or interact with medications you may be taking therefore medical advice and supervision is necessary.
It may impact your driving license, and traces of THC may be found on a roadside drug test. Check your state laws around this.
It is costly because the doses needed for people with epilepsy are high.
There can sometimes be issues with supply, so there may be occasions where you are unable to get your CBD product which can increase the risk of seizures.
You should not stop your anti-seizure medication, CBD is regarded as complementary treatment to be used alongside your medication.
If you have side effects or little effectiveness or decide CBD isn’t for you, then you need to wean off the CBD like any other anti-seizure medication, so you will still be outlaying a lot of money whilst weaning.
If you are thinking of trying medical cannabis it is very important that you first speak to your neurologist or treating doctor.
In early 2017, the Federal Government changed laws to allow easier importation of medicinal cannabis from suppliers overseas.
Access to medicinal cannabis involves a more complicated process than with most other medicines. Most medicinal cannabis products are unapproved therapeutic goods, which means they have not been assessed by the TGA for safety, quality or effectiveness. However, where clinically appropriate, there are pathways for doctors to access medicinal cannabis products for their patients.
This means that you can’t simply go to a doctor, obtain a prescription, and fill it at a pharmacy as you would with conventional registered medicines. A doctor must either be an ‘Authorised Prescriber’ or be prepared to make an application on behalf of their patient through the TGA ‘Special Access Scheme’. It varies in each state, but doctors usually need to be able to show that the product would be of benefit for their patient.
At this time, advertising of medical cannabis is not allowed, so it’s very difficult for both patients and doctors to know what’s available but the Australian medical cannabis market now hosts many medical cannabis products through the Therapeutic Goods Administration (TGA) access pathways. There are also various products that doctors prescribe via compounding pharmacies.
In most states any doctor can prescribe medicinal cannabis for any patient with any condition, if they have the required approvals. In addition to a doctor prescribing the treatment, the legal use of cannabis for medical purposes differs by States and Territories. See below for the regulations in your state.
Federal Government – The Federal Government relaxed medicinal cannabis restrictions in March 2018 and has passed legislation legalising the cultivation of cannabis for medicinal purposes.
It should be noted that people should be advised that they are not able to drive while treated with medicinal cannabis. People should be informed that measurable concentrations of THC can be detected in saliva for many hours after administration (TGA 2024). Speak to your specialist about this if you have concerns.
In this context, we are referring to medicinal cannabis which is prescribed by a registered healthcare practitioner to relieve the symptoms of certain medical conditions. This information is not in relation to unregulated or non-prescribed cannabis products.
Currently the Royal Australasian College of Physicians advises that anyone taking medicinal cannabinoids should not drive.
Different cannabinoids affect the body differently. Therefore, different ratios of cannabinoids in medicinal cannabis products will have varying effects.
Your suitability to drive depends on the type of treatment you have been prescribed, and this should be discussed with your prescribing doctor.
Driving and Cannabidiol (CBD)
There is no evidence that CBD affects driving.
There are no legal driving restrictions for people taking prescription CBD only medicines.
However, like many other medications, CBD can cause drowsiness, fatigue and in some instances lowered blood pressure when first commencing the medication. These symptoms are seen more often when the CBD is taken at high doses or with another interacting medication so extreme caution is required when operating heavy machinery or driving.
Driving and Tetrahydrocannabinol (THC)
In Australia, there is zero tolerance for driving with the presence of Tetrahydrocannabinol (THC) in oral fluid, blood or urine. Even if the driver has a prescription for medicinal cannabis, there is no exemption or legal defence for driving with even a trace of THC.
THC can affect thinking and motor skills necessary for safe driving such as attention, judgement, memory, vision and coordination.
People taking medicinal cannabis need to be aware that THC can be detected in urine for many days after the last dose of medicinal cannabis. It can take up to five days for 80 – 90% to be excreted from the body.
More research is needed in the area of driving and medicinal cannabis but so far the research has shown:
vaporised cannabis containing THC can increase lane weaving and impair cognitive function in a driving simulator
combining cannabis containing THC and alcohol dramatically impairs performance
risks are greatest when a person first starts taking medicinal cannabis containing THC or if the dosage increases.
Unlike alcohol, a direct relationship between blood levels of THC and levels of driving impairment has not yet been established.
Read the Driving Factsheet from the Centre for Medical Cannabis Research
There are no driving restrictions for people taking prescription Cannabidiol (CBD) only medicines.
There is zero tolerance for driving with the presence of Tetrahydrocannabinol (THC) in oral fluid, blood or urine.
You should discuss the impact of medicinal cannabis on your driving with your doctor.
If you have a legal* prescription for medical cannabis from a doctor, then you are able to travel with it. Travelling with prescribed medical cannabis should be no different from any other medication.
Planning ahead will reduce anxiety about carrying medical cannabis across borders and ensure you are following the laws of the country you are leaving.
*a prescription from a medical practitioner who have had the cannabis medicine supplied in accordance with that prescription (i.e. by dispensing through a pharmacist)
When travelling interstate
THC is considered a Schedule 8 drug whilst CBD is a Schedule 4 drug. See the TGA for information about scheduling.
Each Australian state and territory has specific requirements about carrying Schedule 8 and other restricted medications across borders; some require a script written by a local medical practitioner to lawfully possess that product. Queensland and Tasmania have additional requirements for CBD products even though they are not Schedule 8 drugs.
If in doubt about what is required, contact your local state or territory health department.
Carrying medicinal cannabis interstate when travelling by plane has not been tested in a court of law, however, it is generally accepted that medicinal cannabis, as a prescribed medication in the original packaging, will be exempt from confiscation and prosecution for patients travelling between states.
Travelling out of Australia
There are very few restrictions about the medications or medical devices you can take out of Australia. It is important, however, to check if they are permitted to be brought into the country you are travelling to, as well as any country where you will be ‘in transit’. At this point in time it is difficult to fly internationally carrying medicinal cannabis, even if it has been prescribed, as it remains a restricted product in some countries.
Before you leave Australia you should contact the Embassy or Consulate of the countries you intend to visit. Each country has its own required documentation for customs clearance when carrying medicinal cannabis.
Always carry a letter from your doctor stating the name of the medicine, how much you are taking and that it is for your personal use. Keep the medicine in the original packaging for easy identification.
If you will be away for more than three months, ask your doctor about access overseas as not all medicines are available in all countries.
Travelling into Australia
To bring any medical cannabinoid therapy into Australia for personal use you will require what is called a ‘Travellers Exemption’, meaning you must have a medical prescription from a medical practitioner. It is important to note that the standard of documentation for obtaining medicinal cannabis in some counties will not meet the Australian requirements. Foreign documents such as a ‘medicinal cannabis licence’ or a ‘documented recommendation’ will not be sufficient to bring the medicine into Australia.
It is important to keep the medication in the original packaging labelled by the dispensing pharmacist. A copy of the medical prescription should be carried with the medication. Up to three months’ supply may be brought into Australia for personal use and can be carried by the individual or a parent or carer. It is important to check how much medicinal cannabis can be taken out of the country from which you are departing.
Although you can bring three months’ worth of medicinal cannabis into Australia, you can only take one months’ worth out of Canada and nothing out of the United States of America.
Also, if you are ‘in transit’ in another country it is important to check the regulations about carrying medicinal cannabis; some countries have very strict laws which attract significant jail terms for possessing a drug that is not permitted in that jurisdiction.
Always carry medicinal cannabis in the original packaging dispensed from the pharmacist
Carry your medical prescription with the medicine
Carry a letter from your doctor stating the name, dose and personal usage of the medicine
Only bring up to three months’ worth into Australia
Check how much you are permitted to take out of the country you are leaving
Check the legal requirements for each country you are travelling to, as well as any country where you are ‘in transit’
Before leaving, contact the Embassy or Consulate of each country you are visiting for their rules and regulations
Just about all chemical compounds, including prescription, over-the-counter and herbal formulations and some foods can potentially interact with each other. Cannabis-based products are no different.
About 60% of pharmaceutical drugs are metabolised through a pathway of more than 50 enzymes called the cytochrome P450 (CYP450) pathway. The role of this pathway is to process and eliminate toxins in the liver.
Certain substances can increase or decrease how fast other medications or substances are metabolised through the liver.
Cannabidiol can inhibit the CYP450 system of enzymes, meaning it will take longer to metabolise other medications. This can lead to higher doses in your blood stream and unwanted side effects; or signs of toxicity, at lower than expected doses, requiring close monitoring and adjustment of both compounds if needed.
Caution needs to be exercised with blood thinners such as warfarin; anti-hypertensive medications especially when taking THC; sedatives like alcohol and benzodiazepines; narcotics like codeine and some antiseizure medications.
Conversely, some drugs are may decrease the bioavailability of THC by increasing the rate at which the THC is metabolised in the body. This means higher amounts of THC may be needed to gain the same therapeutic benefit. This can significantly increase the cost for the user.
Before starting any form of cannabinoid-based therapies it is worthwhile to check for any potential drug to drug interactions not only with anti-seizure medications but any other prescription, over-the-counter, herbal or supplemental products.
Researchers at the University of Alabama USA studied interactions between CBD and anti-seizure medications. They found significant changes in serum levels for clobazam (Frisium), rufinamide (Banzel), topiramate (Topamax) and eslicarbazepine (Zebinix or ESL) in the presence of CBD. They also noted abnormal liver function tests when CBD was taken with Valproate (Epilim).
Gaston TE, Bebin EM, Cutter GR, Lui Y, Szaflarski JP, 2017, Interactions between cannabidiol and commonly used antiepileptic drugs, Epilepsia, Vol. 58, No. 9, p.p. 1586-92.
Epilepsy Action believes in a thorough pharmacologic and clinical investigation into cannabis to confirm or disprove its safety and anti-seizure potential. We are at the forefront of advocating for increased research into this area of new hope, and assisting through various Government and University constituted Boards and Steering Committees.
For more information and guidance around medicinal cannabis and a wide range of health conditions go to CanGuide.