Cannabis-derived medicinal products - questions and answers

The Royal College of Paediatrics and Child Health and British Paediatric Neurology Association has developed this Q&A in light of recent developments in this area. It advises on the legality and safety of cannabis-based products and considers the evidence base for their potential harms and benefits.

Update: 1 November 2018

From Thursday 1 November 2018, cannabis-derived medicinal products are available on prescription.

The regulations introduced by the Home Secretary, Sajid Javid, to enact this change introduce a definition of ‘cannabis-based product for medicinal use in humans’. Products that meet the three parts of this definition (1. It contains cannabis, cannabis resin, cannabinol or a cannabinol derivative; 2. It is produced for medicinal use in humans; and, 3. It is a medicinal product) – will be rescheduled to “Schedule 2”. Once a product that meets this definition is licensed by the MHRA, it will be available for prescription in the same way as any other Schedule 2 drug.

Next steps

The Advisory Council on the Misuse of Drugs (ACMD) will conduct a long term review of cannabis, and the National Institute for Health and Care Excellence (NICE) has been commissioned to provide advice for clinicians by October next year. The Government has stated that it will monitor the impact of the policy closely as the evidence base develops and review when the ACMD provides its final advice.

The British Paediatric Neurology Association has produced guidance on the use of cannabis-derived medicinal products for children and young people with epilepsy and NHS England has published support for providers. Both can be found via the links below.

Are cannabis-based products legal in the UK?

On Thursday 26 July, the Home Secretary, Sajid Javid, announced that specialist clinicians will be able to legally prescribe cannabis-derived medicinal products by the autumn. 

The Home Secretary decided to reschedule these products after receiving advice from experts during the two-part review he commissioned on 19 June 2018. It means that senior clinicians will be able to prescribe the medicines to patients with an exceptional clinical need. The Department for Health and Social Care (DHSC) and the Medicines and Health products Regulatory Agency (MHRA) will now develop a clear definition of what constitutes a cannabis-derived medicinal product.

Only products meeting this definition will be rescheduled. Other forms of cannabis will be kept under strict controls and will not be available on prescription.

The RCPCH issued a statement following this announcement on 27 July 2018. In this, Dr Mike Linney, RCPCH Registrar and Chair of the Ethics Committee, said:

Cannabis-derived medicinal products have been shown to improve the quality of life for some children suffering with conditions such as severe epilepsy. This decision will come as a relief for these families, as it grants hope for other potential life enhancing treatment options.

Now a decision has been made that cannabis-derived medicinal products will be made available on prescription, we look forward to hearing more from the Department for Health and Social Care (DHSC) and the Medicines and Health products Regulatory Agency (MHRA), who will now develop a clear definition of what constitutes a cannabis-derived medicinal product. However, in the meantime, I must stress the importance of parents not giving children unlicensed cannabinoid oil products. There is currently no clear evidence to suggest that they are safe or effective in treating medical conditions, and there is a serious risk that they will interfere with prescribed medications that the child is taking.

In addition, this ruling will potentially allow further much needed research into the benefits and side effects of cannabis-derived medicinal products.

There are more than 100 active compounds have been derived from the Marijuana (cannabis) plant. Two of these compounds, cannabidiol (CBD) and tetrahydrocannabinol (THC), have been investigated the most for their possible therapeutic potential in medicine. THC is the major psychoactive component of marijuana that is responsible for giving so-called “highs” to recreational users of cannabis. CBD is not psychoactive in this way. Cannabis-based products such as cannabis oils are only legal in the UK if they contain less than 0.2% of THC.

Are there any therapeutic benefits to cannabis-based products for epilepsy?

Epilepsy affects 1-2% of the population of the UK and one third of those will have seizures that are not controlled by currently prescribed medications. There is a legitimate interest among medical professionals and families of children with epilepsy in any new therapies that may improve control of these difficult epilepsies.

CBD as Epidiolex, a pharmaceutically prepared product, has been shown to be moderately effective in two clinical trials in two types of epilepsy, Lennox Gastaut syndrome and Dravet syndrome. There is, as yet, no evidence in from clinical trials that products containing THC are effective or safe in children with epilepsy. There is experimental animal data that shows that both CBD and THC have anti-epileptic effects via different mechanisms. THC may also be proconvulsant. More clinical trials are needed to understand both the relative effectiveness and possible side-effects of CBD and THC.

As there is evidence that use of THC may affect the developing brain and that these changes may be permanent, doctors and scientists have concentrated instead on investigating the potentially less damaging cannabidiol (CBD) as a treatment for epilepsy in children.

What about other conditions?

There is moderate evidence to suggest that cannabis-based products have some benefits in the treatment of other conditions, such as multiple sclerosis, nausea, vomiting and chronic pain. There is limited evidence for the use of cannabis-based products in palliative care, and this evidence is from poor quality studies.

Can my child be prescribed a cannabis-based product if it’s less than 0.2% THC?

It’s our current understanding that cannabis-derived medicinal products will be legal in the UK by the autumn but we are currently awaiting the MHRA and DHSC to define what constitutes a cannabis-derived medicinal product.

There are many so-called “hemp oils” (or cannabis oils) available online and in shops, for example health food stores in the UK. These are sold legally as they contain less than 0.2% THC, but they are not produced to a pharmaceutical standard.  As well as CBD and THC they may well contain other cannabinoids, pesticides and impurities. Independent laboratory testing of these products often reveals that they have different quantities of CBD and THC than is detailed on their label. It has also shown that different batches of the same product have different concentrations of constituents.

These products have not been tested in clinical trials either for safety or for effectiveness.

What are the safety concerns surrounding cannabis-based products?

The problem with some cannabis-based products is that there is a lack of long term clinical studies, so we still don’t know if they are either (a) safe or (b) effective in treating children, and if so, effective and whether this is just for specific epilepsy conditions.

We have some idea of the short term effectiveness and side effects of pure cannabidiol; however, we do not have any robust scientific evidence about other cannabis products.  

We know that there are a number of side effects of cannabidiol use that have been shown in short term (12 week) clinical trials. These include dizziness, diarrhoea, sedation, appetite loss, sedation and decreased liver function. There is also a concern that the use of THC may affect the developing brain and cause alterations to IQ and mental health. 

There is also a strong risk that cannabis-based products will interfere with other medications. There is evidence for interference with any anti-epileptic drugs that are metabolised by the liver (which is many of them), and some strong painkillers. What’s more, most routine medications have not yet been tested for interactions, so the level of risk is unknown.

The cannabis oils may have anti-epileptic effects and there are positive results in some children with epilepsy with a pharmaceutically prepared product with <0.1% THC. However, it would be wrong for these reports to form the basis of treatment policy for the population as a whole; what we need is rigorous clinical evidence of safety and effectiveness when medicines are prescribed.  In addition, products with high concentrations of THC may cause significant damage to the developing brain. 

Consequently, the BPNA and RCPCH do not recommend their use.

I have bought cannabinoid oil and given it to my child – what should I do?

The RCPCH advises that parents do not give their children cannabinoid oil products. There is no evidence to suggest that these products are safe or effective in treating medical conditions, and there is a risk that they will interfere with prescribed medications that the child is taking.

However, if parents already have given these products to their child, we would strongly encourage them to talk to their doctor right away so that they can discuss any risk of side effects which can then be assessed and any potential interactions with other medications discussed, as well as ensuring that the child’s condition can be closely monitored.

The RCPCH fully understands when parents are acting in what they believe is in the best of their child, and support an open dialogue between parents and clinicians.

What about Epidiolex® – can my child be prescribed that to treat epilepsy?

Not currently but this may change soon. Epidiolex is a product of pure cannabidiol (<0.1% THC) which has been clinically tested in the UK, USA and Europe and found to be moderately but significantly more effective than a dummy treatment (placebo) in the control of seizures in two rare forms of epilepsy, Dravet Syndrome and Lennox-Gastaut Syndrome. This product has been developed specifically as an anti-epileptic and has been robustly scrutinised in clinical trials. These trials also showed that CBD had more side-effects than placebo and had interactions with other anti-epileptic drugs (e.g. clobazam and sodium valproate). 

In June, the Food and Drug Administration (FDA) approved Epidiolex® (cannabidiol, or CBD) for treatment of Dravet Syndrome and Lennox-Gastaut syndrome. The approval comes at the end of a four-year series of trials of the benefits of CBD in relieving the symptoms of these seizure disorders, which are highly resistant to existing treatments. The European body – the EMA – is likely to come to a decision by the end of this year.

What about the evidence for the rare epilepsy syndromes?

One pharmaceutical company has produced a pure form of CBD (that contains less than 0.1% THC) – Epidiolex (see above) - and has rigorously investigated its use in two less common and severe epilepsy syndromes, Dravet Syndrome and Lennox-Gastaut Syndrome. They have done this by conducting scientifically rigorous, double-blind, randomised controlled trials. This is the gold standard method of investigating the efficacy of new drugs. These trials have shown that CBD is moderately but significantly more effective than a dummy treatment (placebo) in the control of seizures in these two conditions.  However, the trials also showed that CBD had more side-effects than placebo and had interactions with other anti-epileptic drugs (eg clobazam and sodium valproate).

What do we need to see for children with epilepsy?

Both the RCPCH and The BPNA are very sympathetic to the needs of children with epilepsy and their families.

Our members are devoted to improving the lives of children with epileptic seizures. We are keen to investigate the therapeutic potential of pharmaceutical grade cannabis related products in robust scientific treatment trials and to support the use of scientifically tested and proven treatments in appropriate clinical circumstances. Epidiolex will continue the regulatory process and will likely become available for prescription in due course. A change in the law as described will assist further research into a wider range of products.

We encourage all families who have children with complex epilepsies to consult with their paediatric neurologist to explore the many treatment options that exist and to make informed decisions about the pros and cons of different treatments.