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A high for cannabidiol

Posted on 2 July 2018

A high for cannabidiol

There has been a huge amount of press interest very recently in medical cannabis, its effects, and whether it should be legalised.  This has included the high profile campaigns by the family of Billy Caldwell to allow Billy to use cannabidiol, or CBD, oil extracted from cannabis to alleviate his severe and frequent attacks of epilepsy, and by the family of Alfie Dingley, who also suffers from severe childhood epilepsy.

The Home Secretary, Sajid Javid, has now announced a review into the use and regulation of medical cannabis with the Chief Medical Officer, Sally Davies. In the meantime, both Billy Caldwell and Alfie Dingley will be allowed to use CBD under medical supervision, and the Home Office's original refusal to permit the use which led to the press coverage has been reversed.

We have been working with clients on medical cannabis projects for more than two years. In this article, we summarise the current regulatory and legal position and identify those issues which need to be resolved in order to create a regulatory framework for the legalisation of medical cannabis.


Cannabis is currently categorised as a Class B Drug under the Misuse of Drugs Act 1971 because of its psychoactive properties.  It is therefore a criminal offence to grow, import, sell or use cannabis for recreational purposes.  However, cannabis contains 113 different cannabinoids, with Tetrahydrocannabinol (or THC) being the primary compound with psychoactive properties.

CBD, which can come in a number of formulations, but more commonly in the form of an oil, has no known psychoactive properties. Whilst one might think from the recent press coverage that the sale of CBD in the UK is strictly prohibited, it is not a scheduled product under the Misuse of Drugs Act. Indeed, it is possible to buy CBD oil in Holland & Barratt, where it is marketed as a food supplement.

So, when people speak of 'medical marijuana', it is not always clear what they are referring to.  However, the main plant cannabinoids which are currently believed to be the most important in terms of their efficacy are THC and CBD, and it is CBD, or a formulation of CBD and THC, which is the basis of most therapeutic products on the market.

What is the issue?

There have been many unscrupulous sellers of CBD products who have made unsupported claims that their product can help with anything from controlling cancerous tumours to managing obsessive compulsive disorder, and much in between.  Many of these products had no provenance in terms of their composition or the quality of their manufacture, let alone to GMP standard. 

Also, while an ever expanding body of evidence has been created over the last 30 years or so on the potential therapeutic effects of medical cannabis, for the most part these studies fall well short of establishing the levels of safety and efficacy of these products. 

As a result, on 13 October 2016, the MHRA in the UK published an opinion that "products containing CBD used for medical purposes are a medicine". If formally categorised as a medicine, CBD products must have a marketing authorisation from the MHRA, and, as every pharmaceutical company is aware, this sets stringent standards of proof that the products meet safety, quality and efficacy standards.  Indeed, some cannabinoid pharmaceutical products have been approved by the medicine regulatory bodies in the US and Europe.

The fact that the claims being routinely made for CBD oil or CBD/THC product combinations, (e.g. palliative pain care, spasticity in multiple sclerosis, epilepsy, etc.) are medical claims is undeniable, and no sensible person would contest the MHRA's positon that CBD/THC products are being marketed as medicines, and must be regulated.

The difficulty comes in applying the normal pathway for approving a medicine to CBD/THC products which are whole plant extracts.  The very high cost and considerable time involved in obtaining a marketing authorisation is well known and, for all new medicines being introduced to the market in the normal course of events, this must always be correct.  However, although a number of cannabis related product patents have been obtained and (as noted above) cannabinoid based pharmaceuticals have obtained a marketing authorisation, CBD and/or CBD/THC could not now be patented.  Also, as noted above, there are 113 cannabinoids in cannabis; the cost and time required to subject each of these to the normal level of scrutiny required for a marketing authorisation is likely to be prohibitive. 

Accordingly, there remains a significant question mark over whether pharmaceutical companies will be prepared to invest the level of time and resources to obtain a marketing authorisation for the CBD and CBD/THC products reportedly used in the cases of Alfie Dingley and Billy Caldwell.

The question for the authorities may therefore be: what does the regulation of cannabinoids for medical use look like?  It is in everyone's interest that the product is regulated to the best standards possible in the circumstances but, for those products currently being discussed, the MHRA approach would not seem to be a viable option.

The way forward

There is a very significant body of studies into the effects of cannabinoids compiled over many years.  Professor Michael Barnes in his May 2016 Report provides a comprehensive summary of the position at that time and identifies many of those studies that show good to moderate evidence of the efficacy of cannabinoids for a number of medical conditions.

These studies are by no means adequate to justify any cost of marketing authorisation through the normal process.  Indeed, a number of question marks remain over such fundamental issues of the long term effects of these products.  There even appears to be reasonable support from doctors, with a recent Lancet editorial acknowledging the potential benefits and calling for further research (The Lancet, Vol 17 March 2018, pg 193).

However, a significant contribution to the debate on medical cannabis is likely to be the full report of the Expert Committee on Drug Dependence of the World Health Organisation on CBD.  This is due imminently, but it is worth noting that the Pre-Review Report of November 2017 stated that "CBD is generally well tolerated with a good safety profile."  There would therefore appear to be good evidence to suggest that a CBD and/or a CBD/THC product, manufactured to full GMP standards, can be regulated and authorised for certain limited indications without the need to obtain a full marketing authorisation.  The thorny issue of authorising THC for such products should not be seen as an obstacle, and this is very different to legalising cannabis for recreational use.


The debate around medical cannabis clearly will not go away. It now seems highly likely that the government will embrace this, rather than continue with the Home Office's approach under the previous Home Secretary - which some may describe as one of prevarication. It is hoped that a regime that both protects the public and makes an effective therapy available can be achieved.

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