Cannabis oil for epilepsy
On 1 November 2018, the Government's landmark decision to reschedule some cannabis based products for medicinal use, came into force. The change in law means that specialist doctors in the UK can now prescribe medicinal cannabis to people with a limited number of conditions, including epilepsy. Here we explain what the change in law means for people with epilepsy.
What is cannabis?
Cannabis is made up of hundreds of different components. The most well known are two cannabinoids: CBD - cannabidiol - and THC - tetrahydrocannabinol. These are found naturally in the resin of the cannabis plant.
THC is the psychoactive compound in cannabis. It is responsible for the "high" people feel. The legal limit of THC content in a product, as stipulated by the Home Office, is 0.2%.
CBD is not psychoactive and it is thought to be responsible for many of the medical benefits associated with cannabis.
What is medicinal cannabis?
The Government has defined a cannabis-based product for medicinal use in humans as one that :
Is or contains cannabis, cannabis resin, cannabinol or a cannabinol derivative
Is produced for medicinal use in humans and—
Is) a medicinal product, or a substance or preparation for use as an ingredient of, or in the production of an ingredient of, a medicinal product;”
Guidance around prescribing cannabis-based products
NICE – the National Institute of Health and Clinical Excellence – is drawing up formal guidance on the prescribing of medicinal cannabis. This is expected to be published in October 2019.
In the meantime, the British Paediatric Neurology Association (BPNA) has drawn up interim guidance around epilepsy on behalf of NHS England.
The Association of British Neurologists (ABN) has also drawn up interim guidelines for the use of cannabis-based products in neurology for adults.
Guidance for other conditions is being drawn up the Royal College of Physicians with the Royal College of Radiologists (RCR) and the Faculty of Pain Medicine of the Royal College of Anaesthetists.
Guidance from the Association of British Neurologists (ABN)
Interim guidance from the ABN states that there is only published evidence for the use of medicial cannabis in Dravet syndrome and Lennox-Gastaut syndrome. Prescriptions should only be for cannabidiol.
Although the label Lennox-Gastaut is often broadly attached to severe epilepsies with compatible seizure types and intellectual disabilities, it is important that there is a clear syndromic diagnosis.
Dosing data for adults is currently very limited, although more information is expected shortly.
Guidance from the British Paediatric Neurology Association (BPNA)
The BPNA guidance states that non-licensed medicinal cannabis should only be considered for children who:
- have an epilepsy that does not respond to conventional licensed anti-epileptic medications
- have not responded to the ketogenic diet or who are not suitable for the ketogenic diet
- who are not candidates for epilepsy surgery.
The BPNA states that the current best evidence for medicinal cannabis is CBD, a highly purified liquid, which has been licensed in the US by the Food and Drug Administration and is currently going through the application process for a licence from the European Medicines Agency.
CBD does not contain any significant amount of THC, the component of cannabis associated with producing a ‘high’.
What is the evidence?
The reason that the BPNA is only recommending CBD is that there is some evidence to show that this newly developed drug can be effective in reducing some type of seizures in Dravet and Lennox Gastaut syndromes.
Three double blind randomised controlled trials of pure CBD in children and young people with these syndromes has shown a greater reduction in monthly seizures compared to placebos. There was also a greater reduction in drop seizures in people taking CBD compared to those on a placebo. Further open label studies have shown that it may also have an anti-epileptic effect in the epilepsies in general.
What is the evidence around THC?
While some studies have also suggested that THC may have an anti-epileptic effect, animal studies suggest it can also trigger seizures. There is no evidence from randomised controlled clinical trials for products with higher proportions of THC (more than 0.2 per cent).
Concerns have also been raised about the effect of THC on the developing brain in children and young people. Evidence suggests that chronic exposure to THC can affect brain development, structure and mental health.
There is also no good scientific evidence to support suggestions that the addition of THC in combination with CBD increases the efficacy of cannabis-based medicinal products for children.
“Clinicians should not feel under pressure to prescribe cannabis-based medicinal products until they have undergone proper clinical trials,” says the BPNA.
“We recommend that these products undergo randomised clinical trials for efficacy and safety before they are routinely prescribed in the UK. We welcome the rescheduling of these products from Schedule 1 to Schedule 2 that will enable their investigation in clinical trials.”
Children already on products containing THC
The BPNA also recommends that where children are already taking other cannabis-based products that contain higher proportions of THC, they should be transitioned on to CBD until strong evidence for these products can be produced through clinical trials.
The Government has no plans to legalise the use of cannabis for recreational purposes. Possession of cannabis is illegal. This includes cannabis for medical use unless it has been prescribed for you.
Getting a prescription for medicinal cannabis
Cannabis-based medicinal products can only be prescribed by a specialist. A GP cannot prescribe the medication but could refer you to a specialist.
The specialist will discuss all other treatment options with you first before considering a cannabis-based product.
A prescription for medicinal cannabis would only be given when all other treatment options have been tried or are considered unsuitable, and would only be given if the doctor considers it to be in your best interests.
People always have the option of seeking a second opinion.
Health food shops
There is also a wide range of other cannabis products available on the internet and in some commercial outlets such as health food outlets and from cannabis ‘dispensaries’ internationally. These products are of unknown quality and contain CBD and THC in varying quantities and proportions.
MHRA is working with individual companies to ensure that CBD-based products that make medicinal claims should be licensed and meet safety, quality and efficacy standards to protect public health. To date, the MHRA has licensed no other cannabis based medicinal products as medicines.