By Emily Ledger
Medical cannabis and cannabinoid-based medications are becoming increasingly popular around the world as more countries begin to liberalise their policy on the drug. Pain management is one of the most common reasons for medical cannabis use among patients and it is gradually being considered as an alternative treatment option to opioids. However, little research has been done into how the extended use of cannabis may eventually affect pain sensitivity.
Opioids such as codeine, tramadol, and morphine are routinely prescribed for pain management and there is no doubt in the medical and scientific communities that they are effective for this purpose. However, these medications have a number of side effects that can cause significant disruption to patients’ lives. These include having a high potential for abuse, addiction, and overdose. In addition, studies have revealed that, over time, patients may actually begin to experience increased sensitivity to pain.
In contrast, current evidence suggests that the side effects associated with cannabis – such as drowsiness, dry mouth, ‘high’ feeling – are usually well-tolerated in patients. Cannabis-based medicines also have a low potential for addiction and overdose.
New research also suggests that, unlike opioids, extended use of cannabis medications does not lead to heightened pain sensitivity. This discovery could lead to accelerated uptake of medical cannabis products for pain management.
The study, published in The Clinical Journal of Pain this year, aimed to determine the differences in pain tolerance of people who frequently use cannabis in comparison to those who don’t. It was led by Michelle St. Pierre, a doctoral student at the University of British Columbia.
In order to determine any differences in pain tolerance, the researchers performed a cold pressor task test on both participants who were regular cannabis users and those who were not. A cold pressor task test involves plunging the participants’ hand and arm into icy water and recording their pain responses. This test is also used to identify differences in pain sensitivity associated with opioid use.
As cannabinoids – the main compounds associated with the pain-relieving properties of the cannabis plant – act on some of the same pathways to opioids, the researchers theorised that the study would yield similar results. However, cannabis tests yielded more positive results. This study revealed that cannabis users did not experience a change in their pain responses over the course of the study. These results are promising for the ongoing use of cannabis medications for pain management.
In an interview with Science Daily, St. Pierre stated:
These findings are particularly relevant in light of recent reports of opioid overprescribing and high rates of pain in the population, as it suggests that cannabis may not carry the same risk of hyperalgesia as opioids.
Despite the dangers of opioids being well-known, this class of drugs is still commonly prescribed in cases of acute pain and pain management. In fact, Centers for Disease Control and Prevention revealed that in the USA, there are around 51.4 opioid prescriptions per 100 people. In addition, 2018 figures show that an average of 41 people died per day due to opioid overdose – 35% of these were from prescription opioids.
The increase in pain sensitivity that is linked to prolonged opioid exposure could also put patients at higher risk. Previous studies have shown that patients often develop a tolerance to opioids resulting in them having to increase their dose as it becomes less effective against their pain. At the same time, increased perception of pain can lead to a vicious cycle of dose increases and returning pain.
Although a number of sources have touted medical cannabis as the answer to the ongoing opioid pandemic, evidence to sufficiently support the replacement of opioids for pain management has so far been thin. However, studies such as this one are helping to build on the literature that doctors and prescribers need to feel more confident in considering cannabis-based medicines as an alternative therapy.