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Hot Topics Blog

Can I have medical cannabis on the NHS doctor?

Simon Curtis - 14 Nov, 2019

I’ve been asked this question twice in the last month, once by a 70 year old patient who has taken up smoking weed to control her neuropathic pain (let’s call her ‘Rachel’) and the other a young man (‘Clive’) who is smoking cannabis to help control his chronic anxiety. The simple answer, following the publication of this week’s NICE Guideline on Cannabis-based medicinal products NG144 , is an unsurprising ‘no’. Unless of course you happen to have MS with spasticity for which NICE have approved Sativex, or chemotherapy induced nausea and vomiting for which they have approved Nabilone.

For severe treatment resistant epilepsy NICE concluded that the ‘limited evidence’ did not warrant a practice recommendation for any cannabis-based product. However, they also did not make a recommendation against their use by specialists in severe cases of treatment resistant epilepsy pending further research. For the rare childhood epilepsy syndromes Lennox-Gestaut and Dravet, a separate technology appraisal on the licensed drug Epidiolex (a highly concentrated form of cannabidiol) is due to be published next month.

The new NICE guideline will be welcomed by many, especially the parents of children with severe epilepsy syndromes. High profile cases of these children drove the change in the law a year ago making it legal for medical cannabis to be prescribed by specialist doctors, and for children with these syndromes there is RCT evidence of efficacy for cannabidiol NEJM 2018.

However, the vast majority of our patients who want medical cannabis are like Rachel and Clive. They have disabling long term conditions which we treat with blunt tools often with disappointing results. These conditions generally need a holistic, non-drug, long-term approach for successful management, but one of the unintended consequences of the legalisation of medical cannabis has been an increase in hope and expectation for patients that it may be a solution to their problem. One that for many patients appears to be more attractive and ‘natural’ (Rachel tells me, with a wink in her eye, that her weed is one of her 5 a day) than the licensed and evidence-based ‘chemicals’ we often prescribe.

Living with chronic pain, anxiety or neurological disease is hard, a daily struggle, so this increase in hope is totally understandable. It has led to private clinics to feed the demand, and for patients like Rachel and Clive who cannot afford these clinics it appears to have legitimised illicit, uncontrolled use for medical purposes. We are witnessing a shift in thinking around cannabis since the law change, from recreational drug to bona fide medical treatment, which may encourage such use. Another unintended consequence.

So, what about Rachel and her hope for a treatment to control her chronic pain? Managing these expectations for GPs is hard, but NG144 is quite clear that cannabis based drugs should not be offered for chronic pain unless part of a clinical trial. A recent systematic review PAIN 2018 for chronic non-cancer pain found that cannabis and cannabinoids were just not very effective. To achieve a 30% reduction in pain compared to placebo, the NNT were 25 and there was no evidence they were better than placebo to produce a ≥ 50% reduction in pain. The numbers needed to harm were 6. Similarly last year for neuropathic pain a Cochrane systematic review 2018 found a lack of good evidence that any cannabis based product works for chronic neuropathic pain.

And Clive, who is smoking cannabis to help is symptoms of chronic anxiety? A systematic review of trials of cannabinoids for the treatment of long term mental health disorders has just published Lancet Neurology. The conclusion was that there was no evidence that medical cannabis improved the symptoms of depression, ADHD or PTSD and it was associated with an increase in adverse events. There was a small improvement in anxiety symptoms in some trials, but the quality of the evidence was described as ‘very low quality’.

A valid criticism of these systematic reviews is the ‘rubbish in, rubbish out argument’ as most of the studies are small, low quality and looking at a heterogenous range of products and trials. It is fair to say that we have a lack of evidence, rather than evidence of lack, at this stage. Furthermore, all these studies have been short term so concerns regarding dependence and long-term effects on cognition and mental health have not been addressed.

So, where does this leave us and our patients? GPs are expert at managing patient’s hopes and expectations, and also at working with patients within their own belief systems. Neither Rachel nor Clive will be surprised by the NICE guideline, nor will they be impressed by the recent systematic reviews. The fact it seems to help them is all the evidence they need. But these publications will help us to help our patients at least make informed choices pending further research. There is genuine hope that from this research evidence-based effective treatments may emerge, but the current ‘opioid crisis’ we are seeing in chronic non-cancer pain should make us exercise great caution before recommending any cannabis-based products ahead of a supportive evidence base.

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Vaping - Friend or Foe?

Rob Walker - 10 Oct, 2019

Where are we with vaping? Are e-cigarettes the shining knight to rid the world of cigarettes or dangerous products wrapped up in clever marketing with the ‘unintended consequence’ of luring young people into the world of smoking? Vaping is a subject we have been covering in our Autumn Hot Topics courses, and there has been plenty to discuss and digest over the past six weeks or so! A spate of serious lung injuries and a few deaths in the US, India announcing it will ban e-cigarettes completely, Public Health England standing by its view that they are a much safer alternative to smoking, and inflammatory headlines from news outlets adding fuel to the fire. As doctors it is a bit of a minefield, and a difficult area to navigate with our patients. However, a couple of excellent articles in the BMJ over the last four weeks have been useful to put this all in context (BMJ 2019;366:l5445 and BMJ 2019;366:l5591).

Smoking is BAD. This can be easily forgotten when we discuss the risks of vaping. Most of us will have had family members or friends that have been affected by smoking related illnesses. It took the death of my uncle from lung cancer at a young age to shift my family from a group of predominantly heavy smokers, to mostly non-smokers. So the first question is whether vaping is safer than smoking cigarettes? This BMJ editorial sets out that ‘there is now strong consensus that vaping is substantially less harmful than smoking’ and that is still the line taken by PHE. But what about all those people in the US with serious lung injuries? The BMJ article helps put this in context for us. Yes, these incidents are a serious wake-up call to the potential risks of vaping with 450 cases of severe pulmonary disease and six deaths; however, the outbreak appears confined to the US, where products are not well regulated, and the majority (although not all) of the cases were linked to people adding non-regulated products to the liquid solution, particularly THC. Vaping has been around for about a decade so if acute pulmonary injury was a common adverse effect we would expect to have seen cases elsewhere in the world by now. The BMJ editorial suggests that the circumstances of this outbreak point to faulty devices or contaminants, rather than a problem with vaping per-se. 

So, if current smokers want to quit smoking and are considering vaping, one key message is to use standard devices and not to contaminate or add other products; if they do, the short term risks appear low. But what about long term risks? This is the issue I think many of us are concerned about, and one we do not have an answer to. Most e-cigarettes emit numerous potentially toxic substances but we are likely to need another 10-20 years of epidemiological data before any conclusions can start to be drawn on this question. And it is an important question given recent RCT evidence from the UK (N Engl J Med 2019). This study showed that e-cigs were superior to standard nicotine replacement therapy (NRT), almost doubling the rate of smoking cessation at 1 year (18% in e-cig group vs 9.9% in NRT group). However, in the e-cig group 80% of the successful quitters were still using e-cigarettes at 1 year vs only 9% still using NRT at 1 year. If this is translated more widely with large numbers of quitters remaining on e-cigarettes and long term risks with e-cigarettes do emerge, this strategy may prove to have consequences.

But what about the exposure of vaping to children and young adults? Is vaping the ‘cool’ thing to do? Is this getting a generation of teenagers hooked on a different nicotine based product that will ultimately prove to be harmful, or could it lead to some of them taking up cigarette smoking? This is an area I’m sure many of us have considerable worries over. India has recently announced a total ban on e-cigarettes to stop a ‘youth epidemic’, although one can’t help feel that this decision was largely influenced by India being one of the biggest global producers of tobacco. So what data do we have? This second BMJ article discussed concerns in the US, with data showing a continued increase in vaping in high school students - up to 25% had reported vaping in the previous 30 days (up from 20%). The availability of fruity flavours and trendy devices has been widely attributed to this rise, and has led the the US announcing a ban on most flavoured products. In the UK the latest data from PHE (data up to 2018) shows that although experimentation with vaping in children and young adults is slowly increasing, the absolute rates of regular use remain low with 1.7% of 11-18 year olds vaping at least weekly, with the majority of these users being smokers already; regular (weekly) vaping in those that have never smoked in this age group remains very low at 0.2%, although this rate is rising; but as PHE state ‘The extent to which these young people would have tried smoking if vaping had not been available is unclear’.

So how do we deal with this uncertainty? My view is that we need to resist what seems to be an increasing trend in society by trying to deconstruct complex issues into a simple binary decision of ‘friend’ or ‘foe’. Medicine is never that simple, and we need to disregard the one sided inflammatory news headlines, embrace uncertainty and help our patients make informed choices given the information we currently have. Is vaping safe Doc? Not an easy question, but I hope the background above will allow you to have a more informed discussion with your patient next time…And remember, if you’ve had any thoughts or reflections on this, add these to your CPD log for appraisal, which you can do by clicking the ‘add reflective note’ button at the bottom of this blog through your NB Dashboard.

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