Medical cannabis and neuropathic pain – a case study

Estimated reading time: 9 minutes

David*, a patient from MyAccess Clinics, has been taking medical cannabis for neuropathic pain for over 18 months. He shares how he feels the treatment has vastly improved his quality of life.

Since being prescribed medical cannabis in 2020, David, 53, has seen considerable improvement in his symptoms of neuropathic pain, poor sleep, and low mood. 

The former lorry driver was diagnosed with Hepatitis C in 2008 and two years later, with human immunodeficiency virus (HIV). He had lived with persistent pain for more than a decade prior to his eventual diagnosis with peripheral sensory polyneuropathy.

Peripheral neuropathy is often a result of damage to the nerves outside of the brain and spinal cord, which can cause weakness, numbness, and pain, described as a shooting or burning sensation. The symptoms can be debilitating for patients, with treatments often reliant on opioid medications or treating the underlying cause where possible.

In 2016, as a result of a weakened immune system, David was admitted to intensive care with pneumocystis pneumonia – a fungal infection of the lungs which causes inflammation and fluid buildup and can be life threatening if it’s not treated straight away.

David has also suffered from factor V and protein C deficiency and previously experienced multiple episodes of deep vein thrombosis and pulmonary embolism.

At its worst, David described his persistent symptoms of neuropathic pain as a 10/10 on the Brief Pain Inventory (BPI) score, alongside poor sleep, low mood, and poor quality of life (a European quality of life assessment score of 25/100). David relies on his brother to help him with household chores such as shopping but is able to take gentle exercise such as swimming, in an attempt to improve his health and fitness. 

Prescription painkillers 

Like many patients living with chronic pain, David had tried several medications in the past to manage his symptoms, including ketamine infusions, intravenous lidocaine and lidocaine patches, which he says were difficult to use and did not offer any benefit to his symptoms.

He was previously prescribed a cocktail of strong conventional painkillers, many of which left him experiencing extreme side effects but did not offer much pain relief, including carbamazepine, gabapentin (1,200 mg three times a day), pregabalin (300 mg twice a daily), lamotrigine (200 mg twice a day) and topiramate (25 mg twice a day).

Despite uncertainty over its benefits, for a while David was additionally taking 80mg of oxycontin twice a day, which was later replaced with 200mcg fentanyl patches. Sublingual ketamine 50mg was also tried to help manage his acute pain relief due to the benefit he previously received from ketamine infusions.

Exploring cannabis-based medicines

David first explored the option of cannabis-based medicines in 2015, when his pain consultant on the NHS applied to prescribe the legal cannabinoid medication Sativex – commonly used to treat spasms associated with multiple sclerosis. As this treatment is currently only licensed for MS-related spasticity, the application was unfortunately rejected through the hospital’s medicines committee for NHS funding.

Following the rescheduling of medical cannabis at the end of 2018, David’s GP referred him to a medical cannabis clinic in the UK for an assessment in May 2020. He saw Dr Sunil Arora, a chronic pain specialist at MyAccess Clinics, who considered that David was eligible for medical cannabis and therefore clinically appropriate to be prescribed medical cannabis in addition to his licensed medications with GP support. 

Pictures shown are for illustrative purposes only

At the time of presentation, David was taking a number of medications including co-codamol tablets as required, off-label duloxetine, atorvastatin, temazepam and warfarin. While duloxetine slightly improved David’s mood, it did not provide clear pain relief and was associated with drowsiness and light-headedness.

Additional caution was required prescribing medical cannabis in addition to his warfarin, as in some cases, cannabinoids have been known to interact with coumarins, increasing INR (International Normalised Ratio) levels. David was therefore monitored carefully by his doctors and tested his INR more frequently.

David was also using transdermal fentanyl patches which he changed every two days, as he felt that he was not receiving full symptom relief with the usual dose of every three days.

Starting medical cannabis

In May 2020, David was initiated on a CBD-dominant medical cannabis oil. At his first follow-up, one month after starting medical cannabis, he was taking a dose of 0.7ml twice daily (total daily dose; CBD 14mg, THC 7mg). He reported that whilst he did experience some improvement in pain levels (BPI worse score, 8/10) and other symptoms, he was continuing to experience pain. David was advised by his medical cannabis nurse to try medical cannabis a little longer to see if there was any further improvement

At follow-up in July 2020, the patient’s pain symptoms were still present. The patient had minimal side effects, with no interaction with his warfarin medication. Based on this and with the goal of improving symptom control, the patient was switched to a higher CBD:THC ratio product with a higher THC dose.

He started on 0.3mls three times a day of a balanced medical cannabis oil (total daily dose; CBD 11.25mg, THC 9mg), increasing every two to three days by 0.1ml. David then gradually increased his dose to 0.6mls three times a day (total daily dose; CBD 22.5mg, THC 18mg). 

Following this dose increase, David reported a notable improvement in pain symptoms, and there was no impact on his INR levels. However, he was still experiencing issues with sleep and frequently required sleep medication from his GP. As a result of this, in August 2020, a low night-time dose of a THC-dominant medical cannabis oil (0.5mls equating to 10mg THC) was added to help manage his sleep disturbance. 

One month later, in his next follow up appointment, David noted that his sleep had vastly improved three weeks after starting the nightly dose of a THC-dominant oil and his pain continued to be well managed, with improved sensation and feeling in his lower limbs.

He reported that he was no longer experiencing the intense burning pain and that the medical cannabis was helping him to manage residual symptoms.

One year later

For the past year, David has been taking a stable dose of a balanced medical cannabis oil during the day (in the morning and afternoon) and a THC-dominant medical cannabis oil at night.

At his last follow-up in November 2021, at which point David had been taking medical cannabis oil for 18 months, he reported that his pain and quality of life had improved considerably, with a BPI score of 2/10 (previously 10/10 on presentation) and his quality-of-life score had increased to 60/100 (previously 25/100 on presentation).

David has been able to stop taking temazepam, as he feels it is no longer needed to manage his sleep disturbances and he has gradually been reducing the dose of his fentanyl patch, experiencing slight withdrawal symptoms. David’s GP is working in synergy with the clinic, to help him reduce his other medications.

Despite the length of time he has been taking the medical cannabis oil, David has not developed a tolerance to the treatment and has been able to remain on a consistent long-term dose.

Dr Sunil Arora, Medical Director of MyAccess Clinics continues to treat David, who has been a patient for over 18 months and is due to be seen again next month. He is currently well and stable on his medical cannabis treatment and is looking forward to reducing his other further medications. 

Dr Arora explained:  “The support from David’s General Practitioner has been extremely important in the management of David’s medical cannabis treatment and has allowed us to work closely together on the to reduce the total amount of pain medication the patient is required to take, through shared care arrangements.

“David continues to show good efficacy to his medical cannabis with minimal side effects and a reduction in other prescribed medication which he was previously taking for several years. We have halved his fentanyl patch from 200 to 100mcg over the course of a year and we continue to work with his GP to reduce this further. In my experience, patients with neuropathic pain seem to respond well to a balanced CBD: THC medical cannabis oil and the addition of a THC-dominant oil at night can be extremely useful to aid sleep.”

David commented: “My medical cannabis journey has been lengthy, and it hasn’t been an easy one, but I am glad I persisted, especially in those early days when medical cannabis required one to one import licenses. When starting on medical cannabis, I was extremely open-minded and hopeful around the benefits of medical cannabis. I have experienced minimal side effects throughout my treatment period, having only experienced a slight dry mouth.

“One of the major challenges I faced in the early days was talking about treatment with my family and friends, who had a perception and negative stigma around medical cannabis, especially with concerns around impairment. However, this has not been the case at all. 

“One of the challenges that I feel still exists is the concerns around medical cannabis and driving, whilst understanding the guidance around this, it is something that is often on my mind. I find I can manage this by reducing the use of my high THC oils throughout the day. Since starting treatment my family have now got a broader understanding of medical cannabis, I take 0.8ml of a balanced oil morning and afternoon, and 0.5ml of a high THC oil at night.

“At this dose, I feel my symptom control is good and is achievable from a cost point of view. Over the time I have been with MyAccess Clinics I have found the support from Dr Arora and the team extremely valuable. I now continue to see Dr Arora every three months and look forward to continuing my medical cannabis journey.”

MyAccess Clinics has been prescribing medical cannabis for a range of conditions since late 2019. For more information and to book an initial consultation, visit www.myaccessclinics.co.uk 

*For this case study the name and details of the patient history have been changed to protect confidentiality. Permission to use this case study was provided.

The rescheduling of cannabis under the Misuse of Drugs legislation enables unlicensed cannabis-based products for medicinal use (CBPM) in humans to be available under the provisions for ‘’Specials’’ under Regulation 167 of the Human Medicines Regulations 2012. CBPMs are now classified as a controlled drug schedule 2 under the Misuse of Drugs Act 1971.  The supply, manufacture, importation, and distribution of unlicensed CBPMs in the UK is in accordance with MHRA guidance for medical cannabis 2020.1 

1. Medicines & Healthcare products Regulatory Agency, (2020). The supply, manufacture, importation and distribution of unlicensed cannabis-based products for medicinal use in humans ‘specials. [online] Available at: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/869284/Cannabis_Guidance__unlicensed_CBPMs__updated_2020.pdf [Accessed 19 May. 2020].  

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