Living with chronic pain is a daily reality for millions of people. Unlike acute pain, which is a temporary signal of injury, chronic pain persists for 3 months or longer, but can often affect individuals for years. It can be debilitating, impacting every aspect of a person’s life, from their ability to work and sleep to their mental health and overall well-being. Over the last few decades, opioids have been a common treatment for managing chronic non-cancer pain.
Chronic Pain and Opioid Use
The use of opioids for an extended duration presents its own set of challenges. Long-term opioid use may not always improve pain or function and can be associated with other issues such as elevated symptoms of anxiety and depression. Concerns about tolerance, opioid-induced hyperalgesia (an increased sensitivity to pain), and the potential for opioid use disorder have led many in the medical community to search for other strategies for pain management.
The prescription of opioids for chronic pain management has become less common in recent years; however, many patients remain on opioid therapy. In 2019, 22.1% of US adults with chronic pain were prescribed opioids in the previous three months. In the UK, opioid prescribing more than doubled between 1998 and 2018.
This search has included exploring the potential of medical cannabis in patients with chronic pain, particularly as a way to potentially reduce or “spare” the need for opioids. A retrospective study published in the journal Pain Medicine looked at this very topic, analysing patient records from a pain clinic in California to see if receiving a medical cannabis authorisation was linked to changes in opioid use over time.
The Study’s Approach
The study was a retrospective analysis, meaning researchers looked back at existing electronic health records (EHR) from a large university-based pain medicine center in San Diego, California. They reviewed data from over 3,000 adult patients with chronic non-cancer pain between July 2016 and August 2019.
The primary goal was to measure associations between a patient receiving a medical cannabis authorisation and the amount of opioids prescribed to them over time. The amount of opioids was calculated as opioid milligram equivalents (OME), a standardised measure used to compare the strength of different opioid medications. The researchers were specifically interested in whether patients who received a medical cannabis authorisation would show a reduction in their OME over the study period.
Key Findings of the Analysis
The study’s findings add to the complex picture of medical cannabis’s role in pain management.
- No Statistically Significant Link: The analysis found no statistically significant association between receiving a medical cannabis authorisation and a decrease in opioid use over time. This means the study could not definitively conclude that having a medical cannabis authorisation led to a change in patients’ opioid doses.
- A Noteworthy Trend: Interestingly, a trend was observed in a specific subgroup of patients. Those with a neuropathic pain diagnosis who received a cannabis consultation (an education-based consultation on administration forms and dosing) alongside their authorisation showed a non-significant trend toward a reduction in their OME. However, it is important to know that when a finding in scientific literature is not significant, this means that officially there is no difference.
- Long-Term Opioid Use: The study made a clear and statistically significant finding regarding long-term opioid use (LTOU). Patients with a specific diagnostic code for LTOU had a much higher average OME than other patients, and this use tended to increase over time, regardless of whether they had a medical cannabis authorisation.
Understanding the Study’s Limitations
As a retrospective study that relied on existing EHR data, there are important limitations to consider when interpreting these findings:
- No Confirmed Cannabis Use: The study couldn’t confirm whether patients who received a medical cannabis authorisation actually used cannabis, or how often, what dose, or what form they used. A medical cannabis authorisation only documents that a doctor found cannabis use appropriate, not that the patient acted on it.
- No Clinical Oversight: Unlike European medical cannabis models there is no mandatory clinical oversight to help guide and direct patients on the most appropriate type and dose of medical cannabis.
- Missing Pain Scores: Pain and functional scores were not consistently available in the records, so it was impossible to know if patients experienced a change in their pain relief from adding cannabis without reducing their opioid dose.
- Study Population: The findings are based on a specific group of patients within one large healthcare system, so they may not apply to patients in other health systems or regions.
The Path Forward
This research highlights the need for a careful and individualised approach to patient care, especially for those considering medical cannabis to complement their opioid therapy. The study’s authors suggest that clinicians should focus on providing patients with education, monitoring pain and function at each visit, and coordinating care to help patients safely manage their pain. Ultimately, these results emphasise the need for further, prospective trials to establish a clearer understanding of whether medical cannabis can truly help patients with chronic pain reduce their reliance on opioids.
Disclaimer: This blog post is for informational purposes only and is based on a specific clinical study. It is not medical advice. The efficacy and safety of medical cannabis have not been established. Patients should always consult a qualified healthcare professional before making any decisions about their treatment.