Cannabis Oil; An idiot’s guide

Patrick, 84 this year, is nothing short of a minor miracle.  A bright, intelligent and curious man, had he not been such a heavy and committed drinker, his life might have been very different.  He has always lived in the street where he grew up in the pitiful poverty of the 1930s.  In spite of his sharp intelligence he never broke free from the impoverishment inherited from his parents.  A few years back we were sure he would die.  Following time in hospital and the discovery of an aggressive carcinoma he returned home with a palliative care package to die.  But he didn’t die, he lost a lot of weight as expected and he became very frail, yet he rallied.  He stopped – or was stopped – drinking and came off his seven daily medicines.   In January, while collecting his nutritional drinks to keep up his weight, his daughter asked if I sold “cannabis oil” as Patrick had run out.    Since his cancer diagnosis he had found out about and was taking “cannabis oil” three drops daily under his tongue. “It’s a miracle” she confirmed “And only £50 for 15 mls”.

“Cannabis oil” consumption is only one aspect of a wider use of “medicinal cannabis” to treat a wide range of conditions.  Such has been the pressure on the Irish Government a private member’s Bill to legalise “medicinal cannabis” is currently before the Oireachtas. The debate on the issue is mainly based on testimony from users about the alleged medical benefits.  In the UK, however, the situation is less sympathetic with a strict legal ban on certain cannabis products and more recently a decision to categorise “cannabis oil” as a medicine severely restricting its supply.

The case of a Tyrone child suffering from a severe form of epilepsy and being treated with “medicinal cannabis” in the US has been highlighted in the Irish Times. His mother claims she is unable to return to Ireland because the treatment is “illegal” and her son needs it.   Mother and son are in dire straits.  They are living in the US where medicinal cannabis is legal but costs $50 a day and that’s before the medical and living costs.   So “medical cannabis” is becoming a medical and political hot potato at the moment and for those who, like me when I was asked to supply it, haven’t a clue what it is, here is the idiots’ guide.


There are many strains and varieties of the plant known as Cannabis sativa.  Hemp is the variety mostly associated with fabric manufacture whereas marijuana is a variety associated with dope.  This difference is down to the various amounts of each of the 70 or so cannabinoids that have been identified.  In simple terms; hemp has very little delta 9 tetrahydocannabinol (THC) – the dope molecule – but, a reasonable amount of cannabidiol (CBD).  This might be; 0.2% or 2% or 4%; it is a bit hit and miss.  To be classified as “hemp oil” the plant must not produce oil with more than 0.2% THC.   A European directive allowed for this position and the consequential development of a medically focused “cannabis oil” market regulated as a food product.  That was until MHRA spoiled the party and decided that, since medical claims were being made, “cannabis oil” is a medicine and products offered for sale therefore must have a medicines license.   At this moment, as “cannabis oil” disappears from the health food shops, it is important to understand that because of lack of regulation, they could contain anything and any amount of CBD and some might actually be fake containing only olive oil.


Mostly anecdotal reports or poorly designed trials are the basis of efficacy claims across a range of conditions; cancers, cognitive conditions, nausea & vomiting, autism, sleep disorders, glaucoma, MS, pain & inflammation, Lymes disease and epilepsy; just to mention a few.  Cannabis, it seems, has the real potential to become the universal panacea.

For most conditions, based on the science,  it is fair to say that cannabis treatment lacks evidence of efficacy and where efficacy has been scientifically demonstrated it is only a weak effect and is generally no better than currently available medicines.


An issue seldom considered by the many who have rushed into this lucrative market is that of patient safety.  All cannabis products have potential to cause not only acute toxicity but also long-term problems.  This is well established for cannabis and its impact on the developing and immature brain and is linked to triggering of schizophrenia. Yet we have no way of knowing this risk with the information currently available.

Patrick might not have much to lose but his demise has been blocked most likely by his lack of booze and his medicines rather than his daily drops of cannabis oil. Younger patients, especially those using higher doses and different ratios for epilepsy, for example, might suffer significant consequences in the future.

Terry Maguire is a pharmacist in Belfast.