The Effect of Medical Cannabis on Prescription Opioid Usage for Chronic Pain

The Effect of Medical Cannabis on Prescription Opioid Usage for Chronic Pain

As research into the medical use of cannabis and cannabinoids continues to expand, one of the key areas of interest is their potential to treat chronic pain. The yield of promising results in this area has also prompted many to propose the use of medical cannabis as an alternative treatment option to prescription opioids.

Opioid use has been on the rise over the last few decades, leading to what has become known as the opioid epidemic in North America. In the US, it is estimated that around 10.3 million people were misusing opioids in 2018. Furthermore, 

However, prescription opioid misuse, addiction, and overdoses are not limited to North America. In fact, opioid overdoses continue to affect thousands of lives every year across the globe.

Medical Cannabis and Harm Reduction

Since scientists first discovered that the human endocannabinoid system may work in tandem with the opioid receptors, medical cannabis has been increasingly proposed as a strategy to reduce harm associated with opioid use. Opioids are known to carry a significant risk of addiction and abuse, as well as lethal overdose.

Both animal studies and human trials have yielded results that appear to support this theory. Furthermore, research also suggests that cannabis may be effective in the management of pain conditions – an area where opioids are overwhelmingly prescribed. These findings could support the use of medical cannabis in order to reduce, and perhaps replace, the use of opioids for the management of conditions such as chronic pain.

A recent survey used data collected from various medical cannabis sites across the USA to determine how medical cannabis can affect prescription opioid use. 

Methods of the Survey

The researchers collected data through online convenience sample surveys from patients of three medical cannabis practice sites. A total of 1181 patients responded, however, 656 were excluded due to not using medical cannabis in combination with opioids. A final sample of 525 patients who reported using opioid medications continuously for at least three months for the treatment of chronic pain and were using medical cannabis, were included in the survey.

The Results

The survey was used to collect data such as changes in opioid usage since the start of medical cannabis use; how long this change was sustained; pain levels, functioning, and quality of life since the start of medical cannabis use; and willingness to continue using opioid medications.

Changes to opioid usage

The results from the surveys revealed a significant reduction in opioid usage following the introduction of medical cannabis. In fact, over 85% of respondents reported that they had been able to reduce or stop their opioid usage since using medical cannabis. 

A total of 40.4% of patients reported that they had stopped using opioids altogether. A further 18.4% reported a 75% decrease, 14.1% a 50% decrease, and 12.7% reported a 25% decrease. On the other hand, 13.3% of respondents reported no change in opioid usage, and 1.2% (6) reported increasing their opioid use. 

Furthermore, most respondents who reported a change in opioid usage reported that they were able to sustain this change for over 12 months (65.3%). A further 23.8% (109) claimed that they had sustained this change for between 3-12 months and 10.9% (50) for 0-3 months. 

Other effects of medical cannabis usage

Interestingly, in addition to a reduction in opioid usage, many respondents also reported a reduction in pain levels. A combined total of 88.8% of respondents reported some improvement in pain levels since the introduction of medical cannabis. These changes ranged from a 1%-100% change with 17.8% experience a pain reduction of 1-20%; 22.8% a reduction of 20-40-%, 24.2% a reduction of 40-60%; and 19.4% and 4.6% reporting a reduction of 60-80% and 80-100% respectively. 

Respondents of this survey also reported improvements in ‘ability to function’ (80%) and ‘quality of life’ (87%).

Willingness to continue using opioids

A number of other implications were found following the introduction of medical cannabis for the treatment of chronic pain. In addition to recording patient-reported improvements, this survey also asked patients whether they want to take opioid medications in the future. Almost two-thirds (62.8%) of respondents answered negatively. 

A further 10.7% answered that they wanted to use opioids if they were needed and 26.5% revealed that they did want to take opioid medications in the future. The researchers discovered that age was significantly predictive of desire to continue using opioids with those in the younger age group being 2.0 times more likely to report not wanting to use opioids in the future.


This study represents one of the largest surveys of chronic pain patients who have used opioid medications for a minimum of three months, in combination with medical cannabis. The results from this survey present extremely promising insights into the potential use of medical cannabis in this area with “a remarkable percentage of patients both reporting complete cessation of opioids and decreasing opioid usage”. 

The researchers hypothesise that these results are down to the synergistic relationship of cannabis when used in combination with opioids. It is likely that this potential to improve pain reduction also led to the majority of patients expressing a desire not to use opioid medications in the future. 

The researchers conclude that these results support previous studies that show that medical cannabis can lead to decreased pain and opioid usage. In addition, medical cannabis has also been found to improve function and quality of life.