Medical cannabis has become increasingly available in many countries around the world, including the UK. Specialist doctors in the UK can now prescribe cannabis-based medicinal products (CBMPs) as a treatment option for a wide range of conditions; however, the most commonly reported reason for use is chronic pain. With an estimated 6-10% of chronic pain cases having neuropathic components and conventional treatment options often offering limited relief, there is a need to explore the potential of other options, including medical cannabis, for the treatment of chronic neuropathic pain.
A major review of research studies has been published looking at cannabis-based medicines for adults living with chronic neuropathic pain. This blog post explains what the research found and what it means for patients.
What is neuropathic pain?
Neuropathic pain is a type of pain that comes from damage to or problems with the nervous system. This includes the brain, spinal cord, and nerves throughout the body.
This type of pain feels different from everyday pain. Instead of pain from an injury like a cut or sprained ankle, neuropathic pain happens when the nerves themselves are not working properly or are damaged.
Common conditions that can cause neuropathic pain include diabetes-related nerve damage, pain after shingles, nerve pain from spinal cord injury, and pain related to multiple sclerosis.
Between 6% and 10% of people in the general population experience some form of neuropathic pain. Many people find that currently available treatments do not provide sufficient relief.
What did this research review examine?
Researchers from Germany, the UK, and Canada reviewed 21 studies involving 2,187 adults with chronic neuropathic pain. This review updates a previous version published in 2018.
The studies looked at different types of medical cannabis compared to placebo (inactive treatment). The researchers examined three main types:
- Medicines containing mainly tetrahydrocannabinol (THC)
- Medicines containing a balanced ratio of THC and cannabidiol (CBD)
- Medicines containing mainly CBD
The studies lasted between two and 26 weeks. Participants had various forms of neuropathic pain, including pain from diabetes, HIV, spinal cord injury, multiple sclerosis, and other conditions.
What were the main findings?
The review found that the certainty of evidence for most outcomes was low or very low. This means we cannot be confident about the effects of cannabis-based medicines for neuropathic pain based on current research.
THC-dominant medicines
For medicines containing mainly THC, there was no clear evidence for an effect on:
- Substantial pain relief (50% or greater reduction)
- Patient ratings of much or very much improvement
- Stopping treatment due to unwanted effects
- Serious unwanted effects
These medicines may slightly increase nervous system-related side effects such as dizziness. However, the evidence certainty was low.
THC/CBD-balanced medicines
For medicines with balanced amounts of THC and CBD, there was no clear evidence for an effect on substantial pain relief or serious unwanted effects.
These medicines may slightly increase the number of patients reporting their condition as much or very much improved. They may also slightly increase the number of patients stopping treatment due to unwanted effects. However, these effects were small and may not be clinically meaningful.
CBD-dominant medicines
For medicines containing mainly CBD, there was no clear evidence for an effect on substantial pain relief.
The evidence about other outcomes for CBD-dominant medicines was uncertain. This included patient ratings of improvement, serious unwanted effects, and stopping treatment due to unwanted effects.
What are the limitations of this research?
The researchers identified several important limitations:
Small studies: Most studies included fewer than 50 participants per treatment group. Fourteen of the 21 studies were considered at high risk of bias due to their small size.
Short duration: Many studies lasted only a few weeks. The European Medicines Agency recommends that chronic pain studies should last at least 12 weeks. Only four studies in this review met this criterion.
Excluded participants: Most studies did not include people with serious medical conditions like heart, kidney, or liver disease. They also typically excluded people with current or past mental health conditions. This limits how applicable the findings are to real-world patient populations.
Limited reporting: Some studies did not fully report all side effects, which means the frequency of certain unwanted effects might have been underestimated.
Previous cannabis use: Where reported, between 7% and 91% of participants had used cannabis before. Studies did not distinguish between recreational and medical use. This makes it unclear whether the results apply to people who have never used cannabis.
What does this mean for patients considering medical cannabis?
This research suggests that current evidence about cannabis-based medicines for neuropathic pain is limited and uncertain.
A taskforce from the International Association for the Study of Pain concluded that due to lack of high-quality evidence, the use of cannabis-based medicines is not currently endorsed for pain relief. However, they did not recommend against their use.
Some clinical guidelines consider cannabis-based medicines as a later treatment option for chronic neuropathic pain. This would be after established treatments such as certain antidepressants or antiseizure medications have not provided sufficient relief or were not tolerated.
What should I do if I’m interested in medical cannabis for neuropathic pain?
If you are experiencing neuropathic pain that has not responded adequately to other treatments, you may wish to discuss medical cannabis with a healthcare professional.
At Curaleaf Clinic, our experienced clinicians can assess whether medical cannabis might be a consideration as part of your overall pain management approach.
An assessment would involve:
- Reviewing your medical history and current symptoms
- Discussing previous treatments you have tried
- Considering whether you have any conditions that might make medical cannabis unsuitable
- Explaining potential benefits and risks based on available evidence
- Discussing realistic expectations about treatment
- Medical cannabis is not suitable for everyone. People with certain heart conditions, serious liver disease, current or past psychotic disorders may not be appropriate candidates.
If you are living with chronic neuropathic pain and other treatments have not offered relief, you can complete our eligibility assessment to help you understand whether you could be suitable for a consultation, taking into account your current treatments and medical history.
This blog post is for educational purposes and does not constitute medical advice. Always consult with a qualified healthcare professional about your individual circumstances.
