Medical cannabis vs. Opioid prescribing

Despite the rescheduling of cannabis-based products for medical use in the UK in November 2018, cannabis for medical purposes remains a subject under discussion and scrutiny despite a growing body of evidence for its therapeutic benefits. Here, we look further into some of the problems associated with opioids and explore cannabis as an alternative to opioids for chronic pain. Comparing a “new” medical treatment of medical cannabis against a more widely accepted, conventional treatment. Essentially a debate between two plants - cannabis and the poppy plant. Opioid prescribing The role of opiates in the management of cancer pain and acute pain is well established. Opioids are still commonly prescribed for chronic pain despite the balance of evidence that opioids are neither as effective or safe as we previously thought for the long-term management of chronic pain. Over the past couple of decades it has become clear that doctors have clearly overestimated the benefits of opiates and seriously underestimated their risks. Recent research has shown that long-term and high dose opioid prescribing for patients with chronic pain has increased in the UK despite incompatibility with best practice and the UK now has one of the world’s fastest-growing rates of opioid use. Opioid prescribing rates nearly doubled between the period of 1998 – 2018. Of particular concern is that high-dose prescribing rates are associated with larger practice list size, northern and coastal areas and areas of deprivation. In the US the picture is even more alarming where drug overdose is the leading cause of injury mortality and more than two-thirds of drug overdose deaths involve an opioid. It is estimated that around 130 people are dying every day in the US from opioid overdose. Why are opioids ineffective for chronic pain and what are the risks associated in their use? We understand that opioids play a vital role in the relief of pain for those receiving treatment for cancer, or those who are recovering from trauma or surgery - however, we must better understand what it is we are giving to patients, how much and how often. The Drugs and Therapeutics Bulletin reminds us that we should rarely be using opiates in chronic or persistent pain and we should reconsider the place of all opiates, including tramadol and codeine, for the vast majority of persistent pain patients. Hyperalgesia is a phenomenon seen in repeated opioid use. This is when someone experiences increased sensitivity to pain so repeated and higher doses of opioids are needed over time to produce the same pain-relieving effects. Such patients may find that they end up on synthetic opioids or strong, prolonged released opioid patches. Opioids are also associated with a number of further unpleasant side effects and adverse outcomes which include:

  • Constipation

  • Nausea

  • Sedation

  • Depression

  • Sexual dysfunction

  • Increased risk of falls and fractures

  • Opioid dependence disorder

Why are opioids so dangerous in overdose? Opioids work via our endogenous opioid system by acting as a potent agonist to the mu receptor. Opioid receptors are located in the brain, spinal cord, and gut. In overdose, there is an excessive effect on the portion of the brain regulating respiratory rate, resulting in respiratory depression, reduced level of consciousness and eventually death. Cannabis for chronic pain There is growing evidence demonstrating the efficacy of cannabis to help manage chronic pain in adults. Cannabis appears to be a much safer alternative to opioids and most importantly is not known to cause death in overdose. The endocannabinoid and opioidergic systems are known to interact in many subtle ways and cannabis has been demonstrated to have a role in helping patients reduce opioid doses and wean off entirely in some cases The National Academy of Sciences released a groundbreaking report, “The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research” concluding that cannabis can be used as a medicine to treat a range of medical conditions including chronic pain in adults. As we develop and deepen our understanding of the endocannabinoid system and the clinical application of cannabis-based medicines, there is hope that more patients in the UK suffering with chronic pain can benefit from such treatments.. It is worth noting that in more established medical cannabis markets such as the USA and Canada, patients with chronic arthritic and musculoskeletal pain are the most prevalent users of therapeutic cannabis products. Dr Leon Barron, founder of The Primary Care Cannabis Network says: “In the UK we clearly have a problem of overprescribing of high dose opioids or other addictive medications with high abuse potential such as gabapentinoids. The current prescribing patterns we see in primary care are neither safe nor sustainable in the long term. Poor prescribing habits seem to have become widely accepted as the norm and could be attributed to a number of factors including time constraints on doctors, co-morbidities amongst an ageing population, long waiting times for pain clinics and in some cases the overmedicalisation of patient care. Unfortunately, these types of prescribing habits can result in some very serious adverse consequences for patients”. “There is clearly a need to develop safer and alternative therapies for relief of chronic pain that go beyond opioids and it would be helpful as front-line doctors to expand our prescribing toolbox. With its excellent safety profile, I personally believe there is a role for medical cannabis for patients who have not responded well to non-pharmacological measures and first line analgesics. I also strongly believe that as GPs we need to broaden our approach to chronic pain and wherever possible resist prescribing opioids, exploring all non-pharmacological measures in the first instance”. Some people are concerned that medical cannabis could lead to drug abuse - especially in younger children and adults who are using cannabis to treat medical conditions. We can see from recent studies and real-life situations that medical cannabis is leading patients away from more addictive medicines - such as those which contain opioids - and is eliminating a string of severe side effects. Research shows that a relatively small percentage of people become addicted to cannabis. The lifetime dependence risk of cannabis is around 9%, compared to alcohol with a figure of around 15%. To put this in perspective, the addiction rate for cocaine is around 17%, while heroin is 23% and nicotine is 32% We must not forget however that recreational cannabis use is not without potential harms. Illicit, black market cannabis often contains unknown quantities of toxins, heavy metals and fungal and bacterial elements. Chronic use has been associated with potential neurocognitive impairments particularly in adolescent use, and the psychoactive effects of high THC use and associated impairment can lead to increased personal health and public safety risks. Removing the stigma of cannabis Dr Barron continues: “We need to remove the stigma of cannabis and start talking seriously about cannabis as a medicine. The UK with its conservative approach lags behind other countries that have legalised cannabis for medical use. Patient access in the UK remains limited and problematic. We must start to widen the conversation amongst GPs so we are able to build up our knowledge base to allow us to have informed conversations with our patients.


"We should not be coming from a place of ignorance particularly as patients are becoming better informed and more aware of medical cannabis treatments and may be utilising over the counter CBD for a number of ailments. Our aim as doctors must always be to work in partnership with our patients to ultimately help to relieve suffering and improve quality of life, making sure we are practising within our limitations and that we do no harm in the process. Unfortunately, whilst cannabis remains somewhat of a “taboo” subject it can be difficult for doctors to discuss it in professional circles without invoking its turbulent legal, political, and social history”. At The Primary Care Cannabis Network, we are reaching out to and are working with other organisations and societies so we can educate and advance scientific research.

The aim is to expand the knowledge of cannabis-based medical treatments and focus on academic research, education, key-papers and open discussions.

We focus specifically on the needs of GPs and are creating a community that will enable GPs to confidently work together and with specialists to understand medical cannabis treatments and the various regulatory pathways that exist within the UK.

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