How Does Medical Cannabis Affect Opioid Usage in Chronic Pain Patients

How Does Medical Cannabis Affect Opioid Usage in Chronic Pain Patients?

In recent decades, opioids have increasingly been utilised in the treatment of both acute and chronic pain, despite a paucity of evidence for the latter indication. The introduction of high strength opioid medications and the availability of these products through both the black market and medical prescription have contributed to a drastically high rate of opioid-related deaths – particularly in North America.

The opioid epidemic continues to affect thousands of lives per year in the USA and Canada. However, opioid fatalities are also a growing problem in many other countries, including the UK. While the medical community and lawmakers are yet to find an effective solution, a number of research studies have aimed to understand whether medical cannabis could help to reduce opioid prescribing.

Current Evidence for Use of Medical Cannabis for Chronic Pain

Previous studies in both animals and humans have demonstrated that medical cannabis could reduce pain when given in combination with opioids. While this effect may be synergistic, it has been theorised that the introduction of cannabis may lead to a reduction in opioid doses and even cessation of opioid medications.

One example is a study that aimed to “determine if cannabis may be used as an alternative or adjunct treatment for intermittent and chronic prescription opioid users.” Researchers found that over half of chronic pain patients participating in the study were able to cease all opioid use following the introduction of adjunct medical cannabis.

Another recent study used a sample of patients who from three medical cannabis practice sites in the USA to gauge the effect of medical cannabis on opioid usage.

Aims and Methods of the Study

The primary aim of this study was to determine if and to what extent medical cannabis may be useful in reducing opioid use in chronic pain patients. The authors of the study carried out a sample survey which was completed by registered patients of multiple medical cannabis practices.

A questionnaire was sent out to patients at medical cannabis delivery sites and, after assessment, a total of 525 patients who reported cannabis use in combination with opioids were identified. All of these patients had used opioid-based medications for at least three months to treat chronic pain and were using medical cannabis in combination with prescribed opioid use. The researchers defined chronic pain as that lasting longer than three months.

The survey included questions designed to gauge demographic, details on opioid use both before and during introduction of medical cannabis, and the efficacy and consequences of medical cannabis in reducing opioid use. Three efficacy measures of cannabis use were also used: ‘average pain level’, ‘ability to function’, ‘quality of life’.

The Results of the Study

A significant proportion of participants reported benefits to medical cannabis use in combination with opioid medication. Over 40% reported that they had stopped using opioid medications since the introduction of medical cannabis. In addition, a further 18.4% reported that their opioid use had decreased by 75%; 14.1% of patients reported a 50% reduction in opioid use; and 12.7% reported a 25% decrease. On the other hand, 13.3% of participants reported no change in their opioid use and 1.2% reported an increase in opioid use.

The authors of this study note that age may play a significant part in these results. For example, middle-aged and older patients were, on average, between 5.5 and 5.9 times less likely to report improvement in function when compared to younger participants. In addition, younger patients were also twice as likely to report a desire to stop using opioid medications in comparison to older age groups.  

For the majority of patients who reported either a decrease or complete cessation of opioid use, these results were reported to last for over a year. While a decrease in opioid use was the primary measure of the success of medical cannabis for chronic pain in this study, the researchers also noted some promising results in reference to the patients’ quality of life and ability to function.

A total of 420 patients (80% of the sample) reported that their ability to function had improved since they began using medical cannabis in addition to opioid medications. An even larger percentage of patients (87%) reported that their quality of life had improved.


This study suggests that medical cannabis may represent an effective adjunctive – and potentially, alternative – treatment option for chronic pain patients in the future. However, the researchers note that these results may be partially skewed as participants had sought care at a medical cannabis centre, indicating a willingness to adopt alternative approaches to pain management that may not be held by the population at large.

Nonetheless, these results support continued research in this area in the future endeavour to identify effective and less harmful alternatives to opioid medications.