An Exclusive Interview with Professor Roger Pertwee

When someone is coveted with the same prestigious award as 3 Nobel Prize winners and 16 Fellows of the Royal Society, it is abundantly clear that their contribution to their profession is significant to say the least.

This can be said of Professor Roger Pertwee, who in 2011 was awarded the Wellcome Gold Medal from the British Pharmacological Society for his contribution to Pharmacology and ground-breaking research into cannabinoids.

Having spent most of his professional career based at the University of Aberdeen, Pertwee and his associates have made a significant number of breakthrough discoveries concerning cannabinoids over the last half century, leading to collaborations with some of the worlds most coveted medical professionals, including “The Father of Cannabis” Raphael Mechoulam.

An international figure head for cannabis based research, Pertwee works alongside countless notable societies and foundations including GW Pharmaceuticals, the International Union of Pharmacology, the International Cannabinoid Research Society, the International Association for Cannabinoid Medicines and the Beckley Foundation.

This month, Medical Marijuana had the opportunity to speak with Pertwee regarding his 4 decades worth of research into cannabinoids and his opinion on the current state of cannabis and its potential therapeutic benefits:

The academic research of cannabinoids has come a long way in the past 60 years, which events and findings do you feel are the most outstanding over this period?

(a) The discovery of presence of THC in cannabis, of its structure (in 1964), and that it is the main psychoactive constituent of cannabis.
(b) The development of synthetic cannabinoids as medicines (nabilone and marinol).
(c) The discovery of cannabinoid receptors.
(d) The discovery of endogenous cannabinoids (endocannabinoids) – and hence of the endocannabinoid system.
(e) The discovery that this system plays important roles in both health and disease.
(f) The discovery that cannabinoid receptors have allosteric as well as orthosteric sites.
(g) The discovery that cannabis/certain phytocannabinoids are effective vs multiple sclerosis.
(h) The development of a cannabis-based medicine (Sativex) – encouraged by the House of Lords Select Committee on Science and Technology (1998).
(i) New pharmacological information of potential clinical importance about phytocannabinoids other than THC.
(j) The development of CB1 and CB2 selective agonists and antagonists – i.e. of drugs that are much more potent at activating or blocking CB1 than CB2 receptors – or that are much more potent at activating or blocking CB2 than CB1 receptors.

What are your views concerning individual cannabinoids and whole plant extracts? Can you please explain why whole plant extracts containing cannabinoids & terpenes may be more efficient (pharmacologically) than individual cannabinoids?

Pharmacological actions of only a few of the phytocannabinoids that are known to be present in cannabis have now been discovered. Even so, this has helped to identify a number of potential new therapeutic applications for these compounds when given by themselves or with one or more other phytocannabinoid(s). There is some preclinical data which suggests that one potential strategy for pain relief, might be the co-administration of THC and cannabigerol.

There is also a lot of preclinical evidence that medicines could be developed from drugs that modulate (a) the levels of endocannabinoids in the body or (b) the ability of endocannabinoids to activate cannabinoid receptors following their endogenous release.

Under current UK legislation, cannabis and extracts of cannabis are class B drugs in schedule 1 of the misuse of drugs act, this deems them to have “no medicinal value”. To what degree do you believe the current scheduling of cannabis in the UK and around the world has hindered research, and in turn human health/survival? Was this scheduling ever justified in your opinion?

The problem is the recreational use of cannabis – UK legislation should perhaps treat recreational cannabis and medicinal cannabis/cannabinoids differently.

How many cannabinoids have been identified? And do you think there are more waiting to be discovered?

Cannabis contains at least 104 “phytocannabinoids” plus at least 441 other compounds. It is likely that more compounds will be discovered in at least some strains of cannabis. See also Pertwee’s publication Handbook of Cannabis (Handbooks in Psychopharmacology)

Which cannabinoid do you believe offers the most medicinal benefits?

There is no single plant cannabinoid that offers the most medicinal benefits as cannabis is the source of several compounds that show equally high potential as medicines for one disorder or another. These phytocannabinoids include: tetrahydrocannabinol (THC), cannabidiol (CBD), tetrahydrocannabivarin (THCV) and cannabigerol (CBG). Please note however, that we know very little about the pharmacology/toxicology of most of the phytocannabinoid and non-phytocannabinoid constituents of cannabis.

Many cannabis based medicines and preparations are produced to treat symptoms of illnesses and disease. Do you think that in the future cannabinoids may also offer some preventative opportunities, e.g. in being widely prescribed like such drugs as statins?

Currently, the main cannabis-based medicine is Sativex. There is evidence (e.g. from preclinical research) that as well as ameliorating the signs and symptoms of multiple sclerosis, it may slow the progression of this disorder.

In your opinion, is raw well grown cannabis, and cannabis extractions safe enough now for use without full clinical trials, if prescribed correctly?

Full clinical trials with all previously untested cannabis or cannabis extracts should always be carried out as the chemical content of cannabis/cannabis extracts can vary considerably.

What effects do you think cannabinoid based medicines would have on the existing pharmaceutical industry if they were easier to access? Which particular illness or diseases do you feel will be more effectively treated with cannabinoids?

They are likely to affect the pharmaceutical industry more after additional clinical data have been obtained from new clinical trials. Preclinical data predict very many clinical targets for one or more phytocannabinoids –e.g. epilepsy, schizophrenia (including negative symptoms), depression, eye disorders, gastrointestinal disorders, stroke, diabetic nephropathy, neurodegenerative disorders such as Parkinson’s disease, obesity, diabetes, drug dependence (e.g. nicotine dependence), atherosclerosis, osteoporosis, post-traumatic stress disorder, hypertension, Tourette syndrome, nausea and vomiting, cancer etc etc etc. The need now is for some clear clinical data.

Have there been any anecdotal stories you have heard regarding cannabis based medicines that have really surprised you?

Yes – particularly about multiple sclerosis back in the 1980’s and 1990’s – see my contribution to “The Medicalization of Cannabis. Witness Seminar Transcript. Volume 40. The Wellcome Trust Centre for the History of Medicine, at UCL.”

See also my contribution to the Report on Cannabis by the House of Lords Select Committee on Science and Technology (1998).

I actually co-authored a paper based on some anecdotal stories/claims about cannabis and multiple sclerosis. See “The perceived effects of cannabis smoking in patients with multiple sclerosis”.

I think anecdotal stories regarding cannabis based medicines/medical marijuana should not be ignored as they may well lead to the identification of important disorders that could best be treated with a cannabis-based medicine.

If you received a diagnosis of cancer would you be tempted to introduce or to use cannabinoids in your personal treatment regime?

Not without more clinical data – and then probably only using a licensed cannabinoid medicine.

The Handbook of Cannabis (Handbooks in Psychopharmacology) edited by Roger Pertwee is available to purchase now.