There are three forms of licensed cannabis derived medicine available on prescription through the NHS in the UK in treating patients with Epilepsy, MS or Chemo induced sickness.
On this page we talk about medical cannabis for epilepsy and who it is suitable for.
‘Medical cannabis’ Is an umbrella term used for a range of cannabis derived medications, of which are predominantly unlicensed. These medications are extracted from the cannabis flower. Doctors may know these medicines as CBMPs (cannabis based medical products) and this is how the Government refers to these medicines.
The cannabis plant contains over 147 discovered compounds known as cannabinoids, the two most researched and commonly known are cannabidiol (CBD) and tetrahydrocannabinol (THC), however research trials in other “minor” cannabinoids has been carried out in epilepsy, however research is ongoing.
These medications are split into two generations.
First Generation
The cannabis plant like Roses or Daffodiles, has many thousands of varieties or what’s known as “cultivars”. Across these over 147 different cannabinoids have been discovered which the cannabis plant produces. When one of these cannabinoids is
separated (isolated) and a product is manufactured these are known as first generation medicines. An example would be Epidyolex or MRX which has one active ingredient (Cannabidiol), another example is MRX2 which has isolated CBD and THC
and formulated with a mixture of the two at a set ratio.
Second Generation
As above, these are manufactured to contain the full range of cannabinoids present in that particular cultivar of cannabis plant. These do vary between medicines from just a few cannabinoids, to many. Your prescribing clinician should know the differences.
CBD does not have the mood-altering effects often associated with cannabis. There has been a lot of scientific research into CBD as an epilepsy treatment.
THC is the part of the cannabis plant that makes people feel ‘high’. Patient outcome data through observational clinical studies have shown in small quantities, THC is well tolerated with some side effects, however further evidence is needed to know long term impact.
Cannabidiol is the only cannabis-based medicine approved for treating epilepsy in the UK. It is a highly purified liquid containing CBD. It contains trace amounts of THC, but not enough to affect the brain or cause any psychotropic “high” effects.
The brand name for cannabidiol is Epidyolex. This is only available on the NHS for some adults and children with certain types of epilepsy. It is not suitable for children under 2 years old.[1]
There are unlicensed cannabis medicines which have not yet undergone clinical trials, these are prescribed in exceptional cases through the NHS, but predominantly only available privately.
[1] EMC (2024) Epidyolex 100 mg/ml oral solution – Patient Information Leaflet (PIL) – (emc). Available at: https://www.medicines.org.uk/emc/product/10781/pil#about-medicine (Accessed: 28 October 2024).
Epidyolex is a first generation cannabinoid medication. NICE (National Institute for Health and Care Excellence) guidelines set out how medicines can be prescribed in the NHS.
NICE recommend Epidyolex if you, or a child over 2 years old has:
Epidyolex is only recommend if you have already tried 2 or more epilepsy medicines to control your seizures.
Your doctor should check that Epidyolex is controlling your seizures regularly. They should check how often you are having seizures every 6 months. Your treatment will stop if your seizures don’t
reduce by at least 30%. This is compared to the number of seizures you had in the 6 months before starting treatment.
You will need to take Epidyolex with clobazam if you have Dravet syndrome or Lennox-Gastaut syndrome. 2,3
Before prescribing medical cannabis, your specialist will talk to you about:
Your specialist should talk to you about the pros and cons of taking Epidyolex? medical cannabis. This will help you make an informed decision about your care.
You should not use any cannabis products you have not been prescribed while taking Epidyolex.
When prescribing cannabis-based medicinal products, advise people to stop any non-prescribed cannabis, including over-the-counter, online and illicit products. If your doctor won’t prescribe Epidyolex and you don’t agree, our campaigns team would like to hear from you. Contact them at campaigns@epilepsy.org.uk
Medical cannabis and pregnancy and breastfeeding
You should not take Epidyolex while you are pregnant unless the benefits outweigh the potential risks. Talk to your epilepsy specialist if you are pregnant or thinking about getting pregnant.
Does Epidyolex cause side effects?
Like all medicines, Epidyolex can cause side effects. The most common side effects may happen in more than 1 in 10 people. These include:
You can get more information about side effects from the Epidyolex patient leaflet.
Does Epidyolex interact with other epilepsy medicines?
Epidyolex can affect how well other epilepsy medicines work. This includes lorazepam, phenytoin, and valproate.[3]
Epidyolex can also affect how well other medicines work. For example, medicines used to treat acid reflux, such as omeprazole. Talk to your doctor or pharmacist before starting or stopping other medicines.
Can people with other types of epilepsy get a prescription for Epidyolex?
There is some evidence that CBD may be effective for other types of epilepsy. This evidence is not good enough for NICE to recommend it.[1] Research into CBD medicines is ongoing. NICE has called for more research for using it in severe, treatment resistant-epilepsy with one due to begin in 2025 using Ananda Pharmaceuticals MRX formulation.
RESCAS is the Refractory Epilepsy Specialist Clinical Advisory Service. This is an advice service for specialists who would like expert help for complex cases. You can discuss a referral to this service with your child’s specialist. They may be able help if your child’s epilepsy is complex and isn’t responding to treatment.
[1] Lattanzi, S. et al. (2021) ‘Highly Purified Cannabidiol for Epilepsy Treatment: A Systematic Review of Epileptic Conditions Beyond Dravet Syndrome and Lennox–Gastaut Syndrome’, CNS Drugs, 35(3), p. 265. Available at: https://doi.org/10.1007/s40263-021-00807-y.
[1] NICE (2021) Cannabis-based medicinal products Available at: https://www.nice.org.uk/guidance/ng144/chapter/Recommendations#severe-treatment-resistant-epilepsy (Accessed: 30 October 2024).
[2] EMC (2024) Epidyolex 100 mg/ml oral solution – Patient Information Leaflet (PIL) – (emc). Available at: https://www.medicines.org.uk/emc/product/10781/pil#about-medicine (Accessed: 28 October 2024).
[3] British National Formulary (no date) Cannabidiol | Interactions | Available at: https://bnf.nice.org.uk/interactions/cannabidiol/ (Accessed: 31 October 2024).
[1] NICE (2019) Cannabidiol with clobazam for treating seizures associated with Dravet syndrome Available at: https://www.nice.org.uk/guidance/ta614/chapter/1-Recommendations (Accessed: 28 October 2024).
[2] NICE (2019) Cannabidiol with clobazam for treating seizures associated with Lennox–Gastaut syndrome Available at: https://www.nice.org.uk/guidance/ta615/chapter/1-Recommendations (Accessed: 28 October 2024).
[3] NICE (2023) Cannabidiol for treating seizures caused by tuberous sclerosis complex Available at: https://www.nice.org.uk/guidance/ta873/chapter/1-Recommendations (Accessed: 28 October 2024).
Since 2018, a range of second generation cannabis based medicines have been available through private clinics. These are CBD dominant, although contain a range of other cannabinoids including a small amount of THC.
NICE have only made recommendations about prescribing medicines containing CBD for epilepsy. They have not yet made any population wide prescribing recommendations about medicines containing CBD ,THC and other cannabinoids. However, in March 2021, NICE did publish a clarification that
“The fact that NICE made no such population-wide recommendation should not however be interpreted by healthcare professionals as meaning that they are prevented from considering the use of unlicensed cannabis-based medicinal products where that is clinically appropriate in an individual case. Patients in this population can be prescribed cannabis-based medicinal products if a tertiary paediatric epilepsy specialist considers that that would be appropriate on a balance of benefit and risk, and in consultation with the patient, and their families and carers or guardian.”
These are children with severe epilepsy. An unlicensed medicine is not been approved by NICE . Evidence suggests these medicines may be effective. But the research so far is limited and of low quality. Specialists can legally prescribe unlicensed medicines on a case-by-case basis.
The reasons your specialist may prescribe unlicensed medicines with THC include:
NICE has called for more research into medicines containing CBD and THC. This means some people might be able to access these medicines by taking part in clinical trials. Your specialist will be able to tell you if there are any clinical trials you could take part in.
In 2025, A big study into using CBD and THC will start in 2025. Researchers from University College London and Great Ormond Street Hospital will look at how CBD and THC can help can help adults and children with treatment-resistant epilepsy. Read more about this research.
You can buy CBD products in health shops and high street pharmacies. This includes CBD oils and food supplements. But there is no guarantee that these are good quality products. These products tend to only contain very small amounts of CBD, so it’s not clear what effect they would have. Many cannabis-based products are also available to buy online. But their quality and content is not known. They may be illegal in the UK and potentially dangerous.[2]
Can CBD products trigger seizures?
Research has also shown that CBD can affect how well epilepsy medicines work.[3]
Do not stop taking your epilepsy medicine without speaking to your specialist. Stopping suddenly could cause more frequent or severe seizures.
These are illegal and unregulated; they generally contain high levels of THC which are not appropriate to treat epilepsy or synthetic cannabinoids which can be very dangerous to health. Being unregulated, products can contain heavy metals, ethanol, e-coli and salmonella.
We strongly advise that people diagnosed with epilepsy do not smoke, eat or vape illicitly sourced cannabis to treat epilepsy. There is not enough scientific evidence to know how it effects epilepsy. We don’t know if it makes symptoms better or worse. THC at the wrong dose is known to be pro-convulsant.[1] We don’t know the quality, ingredients and strength of cannabis bought illegally. You could be smoking, eating or vaping chemicals from unknown substances. This includes pesticides used when growing the cannabis.[2]Non prescribed cannabis can make some existing mental health symptoms worse. It has also been linked with the possible development of mental health issues.[3] These mental health problems are seen more clearly in people aged 10-19 than in adults. Using a lot of recreational cannabis use can affect their brain development.
Mixing cannabis with tobacco increases the risk of heart problems and various cancers.[5]
[1] Li, J. et al. (2023) ‘Use of non-medical cannabis in epilepsy: A scoping review’, Frontiers in Neurology, 14, p. 1132106. Available at: https://doi.org/10.3389/fneur.2023.1132106.
15 NHS Inform (2022) ‘Cannabis’ Available at: https://www.nhsinform.scot/healthy-living/drugs-and-drug-use/common-drugs/cannabis/ (Accessed: 22 October 2024).
16 Balamurugan, E. et al. (2013) ‘Perceived trigger factors of seizures in persons with epilepsy’, Seizure, 22(9), pp. 743–747. Available at: https://doi.org/10.1016/j.seizure.2013.05.018.
[2] Taylor, A. and Birkett, J.W. (2020) ‘Pesticides in cannabis: A review of analytical and toxicological considerations’, Drug Testing and Analysis, 12(2), pp. 180–190. Available at: https://doi.org/10.1002/dta.2747.
5] World Health Organisation Tobacco Available at: https://www.who.int/health-topics/tobacco#tab=tab_1 (Accessed October 31 2024)
1] Guy’s and St Thomas’ NHS Foundation Trust (2021) Unlicensed medicines – Overview Available at: https://www.guysandstthomas.nhs.uk/health-information/unlicensed-medicines (Accessed: 31 October 2024).
[2] NHS (2022) Medical cannabis Available at: https://www.nhs.uk/conditions/medical-cannabis/ (Accessed: 31 October 2024).
[3] Gaston, T.E. et al. (2017) ‘Interactions between cannabidiol and commonly used antiepileptic drugs’, Epilepsia, 58(9), pp. 1586–1592. Available at: https://doi.org/10.1111/epi.13852.
[1] British Paediatric Neurology Association (2021) Guidance on the use of cannabis-based products for medicinal use in children and young people with epilepsy BPNACBPMsguidanceupdatedOct2021_8b7f3bbc1af32e3ef188b6274100591f (2).pdf