Authors: Lauren Pulling, Roisin Conneely
Today, 26 March, marks Purple Day; an international grassroots effort dedicated to increasing awareness about epilepsy across the globe. This year, we’re taking the opportunity to delve into what can be seen as a controversial area – the use of cannabis-derived therapeutics for the treatment of epilepsy. Historically, the use of such agents has been reported to improve symptoms in a number of neurological disorders, but research into the mechanisms behind this and the risks involved remains limited. However, in the past year alone, we’ve seen positive results in a number of studies investigating the use of cannabidiol, for example in the reduction of seizures in patients suffering from Lennox-Gastaut syndrome, suggesting these products could soon become more commonplace in the therapeutic landscape.
To find out more about the current status of the use of cannabis-derived therapeutics in the treatment of epilepsy, we spoke to Hannah Cock, Clinical Advisor for Epilepsy Action (UK), Professor of Epilepsy & Medical Education and Consultant Neurologist (St George’s, London, UK).
Could you give us a brief overview of the current consensus on the use of cannabinoids in the treatment of epilepsy?
The use of cannabinoids in the treatment of epilepsy is far from simple. Research suggests that there is promise, but there are also risks and unknowns about it.
There are a few parts of the cannabis plant that may have potential for treating epilepsy. These include cannabidiol (CBD) and tetrahydrocannabinolic acid (THCA). There are very few studies on THCA, but there are suggestions that this may have some medical properties in reducing muscle spasms. However, this part of the cannabis plant has a link with the part that gives the experience of a ‘high’ – tetrahydrocannabinol (THC). This means that as well as there being little evidence on how effective it is, it is also currently illegal in many countries. In the UK, THC and THCA are illegal under the Misuse of Drugs Act 1971.
CBD is, however, the part of the cannabis plant that holds a lot of promise as a possible new treatment for epilepsy. CBD is believed to have anti-epileptic effects and does not cause a ‘high’. At the moment, it is the subject of a lot of research, but as yet there is no CBD medicine currently available for routine prescription in the UK.
In October 2016, the government’s Medicines and Healthcare products Regulatory Agency (MHRA) put out a statement about products containing CBD. They stated that such products used for medical reasons are a medicine.
In the UK however, any medicine must have a licence before it can be legally sold, supplied or advertized, and at the moment there is no CBD medicine that is licensed for epilepsy in the UK.
In very rare, exceptional cases, doctors can make an individual decision to recommend an off-licence product. An off-licence product could be a potential new medicine that has not received a licence yet. It could also be a medicine that is licensed for use for a different condition, but may have helpful effects for another condition. There are also ongoing clinical trials for which some patients may be eligible.
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What data on the efficacy and safety of the use of cannabinoids have been presented so far? What are the main benefits and risks associated with this form of therapy?