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Why is the UK behind the curve on prescribing medical marijuana?

Last week, Costa Rica joined the ever-growing list of countries that have legalised marijuana for medical purposes and allowed its cultivation for industrial use.

Last week, Costa Rica joined the ever-growing list of countries that have legalised marijuana for medical purposes and allowed its cultivation for industrial use.

President Alvarado has supported the passing of the bill, saying it will be “of great benefit” to Costa Rica, with supporters saying it will boost the agricultural sector and provide employment opportunities as well as offering health benefits.

While the legalisation of medical cannabis is becoming more widespread, how you qualify for a prescription varies greatly from country to country.

In the US, for example, you may qualify for treatment with medical marijuana if you have a condition such as Alzheimer’s, Crohn’s disease, hepatitis C, AIDS, glaucoma, posttraumatic stress disorder (PTSD), and chronic pain.

However, in the UK, where cannabis was legalised for medical use in 2018, you are only likely to receive a prescription if you have a rare, severe form of epilepsy, are suffering with vomiting or nausea as a result of chemotherapy or if you have muscle stiffness or spasms caused by multiple sclerosis (MS).

For this reason, it is still very difficult for patients to gain access to cannabis-based products on the NHS, and very few prescriptions have been written to date.

Why is it so difficult to get a medical marijuana prescription in the UK?

Medical cannabis is becoming an increasingly popular alternative to traditional pain-relieving medications, but according to the NHS, the evidence is “not yet strong enough to recommend it for pain relief.”

The British Medical Journal (BMJ) explores this issue in detail1, and says that while there is a lack of double-blind randomised control trials (RCTs) – which are considered the “gold-standard” of proof – there is strong personal evidence from patients that medicinal cannabis can be, in some cases, “life-changing”.

This personal evidence is highly suggestive of a “pattern of evidence which should be taken seriously rather than summarily dismissed,” according to the BMJ, yet doctors often do not include this evidence when issuing prescriptions.

The BMJ say the heavy reliance on data from placebo-controlled trials is “misplaced”, as there are more than 50 medicines or indications that have been licensed by the Drug Administration and/or European Medicines Agency between 1999 and 2014 without RCT data.

While RCTs remain an important part of medicine, the BMJ suggests it is time for an ideological shift that would see health professionals begin to accept and rely on data from observational research.

Project Twenty21

One example of a study which makes use of observational data is Project Twenty21. When it was launched in 2019, the project expected to be the largest body of evidence on medical cannabis in Europe, with the aim of enrolling up to 20,000 UK participants in the research.

The project was backed by the Royal College of Psychiatrists (RCP) and aimed to convince policy makers that the drug should be made widely available at affordable rates.

The report, which was the first published real-world data to be collected on medical cannabis in the UK, found that more than half (51%) of patients said using the drug improved their health and ability to lead a normal life.2

The findings also demonstrated significant improvements in patients’ ability to manage debilitating secondary conditions such as anxiety, insomnia and depression.

Others, mostly those suffering with chronic pain, said medical cannabis prescriptions provided a welcome alternative to commonly prescribed medicines that have a high risk of dependency and other serious side effects.

Following the report’s publication, Professor David Nutt, Founder of Drug Science, the organisation behind Project Twenty21, said that while a lack of clinical evidence had made it difficult for doctors to “confidently prescribe legal medical cannabis in the UK”, he hopes the findings would “help to clarify the benefit these medicines can have for thousands of seriously ill patients.”

However, despite these high expectations, little has changed since the research was published in May last year. The authors of the study largely blame the Covid-19 pandemic, which lowered the number of people involved in the trial and took the spotlight away from other health issues.3

Nonetheless, Project Twenty21 will continue for at least another year, which the authors hope will help them to move closer to their long-term goal of “providing enough high-quality UK-based evidence around the benefits of medical cannabis to open up NHS funding for these medicines.”3

Medical marijuana for older patients

Despite the lack of UK data, hundreds of studies conducted in other countries have considered the effects of medical marijuana.

While the drug has mainly been shown to reduce pain, some observational research suggests it could help improve outcomes in patients with conditions such as Parkinson’s disease4, glaucoma5, and rheumatoid arthritis6, all of which are common in older people.

In fact, in recent years, the number of people aged 65 and over using medical cannabis has increased by more than 8-fold, from 0.5% in 2006 to 4.2% in 2018.7

Cannabidiol, or CBD, has seen a particular spike in use in the US, and it is now estimated that 6.4% of adults aged 45 to 55 and 3.7% of those 55 or older have used CBD at least once since 2018.7

This trend has been driven by several factors according to Dr Marc Agronin, including reduced stigma, the easing of restrictions on possession and sale in more countries, and increased media attention, which has led to a huge increase in the number of articles and advertisements which promote the drug and its supposed benefits.7

While various research highlights the benefits for many conditions that afflict older people, including chronic pain, peripheral neuropathy, stress, anxiety, depression, insomnia, headaches, and the adverse effects of chemotherapy, Dr Agronin warns that the use of medical marijuana and CBD in older adults must be approached with caution, as there are several potential adverse effects.

Potential harms of medical cannabis

Dr Agronin notes that heavy marijuana use in both young and middle-aged adults can cause mild functional and structural brain impairments affecting attention, processing speed, motor coordination, verbal memory, and executive function.

It is particularly important, he says, to be aware that these affects may be amplified by pre-existing brain impairment as well as by underlying pulmonary and cardiovascular conditions, especially when medical marijuana is smoked or vaped.

Adverse effects detected in research frequently consist of dizziness and drowsiness, and Dr Agronin says clinicians should be particularly aware of these side effects in older patients with pre-existing neurocognitive impairment such as in Alzheimer’s disease.

Some side effects which are not as well-documented include changes in mood and cognition, psychosis, increased heart rate and blood pressure, urinary retention, and blurred vision.

These side effects are highlighted in one review of 184 older patients (with a median age of 82), which found that after six months of medical marijuana use, while 80% reported some benefit for the treated symptoms, one third reported adverse effects, including dizziness (12%) and sleepiness and fatigue (11.2%).7

Similarly, a systematic review8 found that minor adverse effects (such as drowsiness and dizziness) were common and reported in over half of the studies included in the review. While serious harms were not as common, they were reported in around a third (36%) of reviews that reported adverse side effects.

Overcoming prescribing challenges

While the potential harms of medical cannabis use are evident, the likelihood of serious harm occurring appears to be relatively small. Even so, Dr Agronin says that more rigorous scientific studies are needed to substantiate the proposed benefits of cannabis and fully understand the range and impact of common adverse effects.

And while the BMJ agrees that more research needs to be done, they suggest that the data currently available provides enough evidence to suggest that medical marijuana has the potential to offer improved quality of life for those who are currently prescribed medicines that are either ineffective or poorly tolerated.

The BMJ notes that the drug also offers the potential of a significant cost saving to the NHS in terms of reduced hospital stays and less prescribing of other medicines, particularly opioids for chronic pain.

Now, in the UK, they hope that policymakers and prescribers will take the time to “understand the challenges to prescribing” and in turn develop approaches to overcome the current “highly unsatisfactory situation.”

References

  1. Nutt D, Bazire S, Phillips LD, et al. So near yet so far: why won’t the UK prescribe medical cannabis? BMJ Open 2020;10:e038687. doi: 10.1136/bmjopen-2020-038687
  2. Sakal, M. Lynskey, A. K. Schlag, D. J. Nutt. Medical Cannabis improves Quality of Life by over 50% – Preliminary Results from Project Twenty21. Drug Science 2021 [online] available at: https://www.drugscience.org.uk/medical-cannabis-improves-quality-of-life-by-over-50-percent-results-from-project-twenty21/
  3. Project Twenty21 in 2022: A Message for Patients. Drug Science 2021 [online] available at: https://www.drugscience.org.uk/project-twenty21-in-2022-a-message-for-patients/
  4. Yenilmez, Ferhat et al. ‘Cannabis in Parkinson’s Disease: The Patients’ View’. Journal of Parkinson’s Disease, vol. 11, no. 1, pp. 309-321, 2021. DOI: 10.3233/JPD-202260
  5. Tomida I, Pertwee RG, Azuara-Blanco A. Cannabinoids and glaucoma. British Journal of Ophthalmology 2004;88:708-713.
  6. Gonen T, Amital H. Cannabis and Cannabinoids in the Treatment of Rheumatic Diseases. Rambam Maimonides Med 2020;11(1):e0007. Published 2020 Jan 30. doi:10.5041/RMMJ.10389
  7. Agronin, E. The Age of Cannabis Has Arrived: Issues for Older Adults. Psychiatric Times, Vol 38, Issue 3, Volume 03. 2021. [online] available at: https://www.psychiatrictimes.com/view/age-cannabis-has-arrived-issues-older-adults
  8. Pratt, M., Stevens, A., Thuku, M. et al. Benefits and harms of medical cannabis: a scoping review of systematic reviews. Syst Rev 8, 320 (2019). https://doi.org/10.1186/s13643-019-1243-x

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