Introduction

The reliance on opioids to relieve symptoms in chronic pain can be extremely detrimental to health and well-being. Not only are opioids not effective in the management of chronic pain long-term, but they are also extremely addictive. Hence, it is important to assess other options for the treatment of chronic pain to replace over-reliance on opioids. So, how can opioid use be minimised?

One option is the replacement of opioids with medical cannabis, which has been used to manage pain for thousands of years across the world. Below, we will dive into how medical cannabis can reduce the reliance on opioids in chronic pain. 

Exploring Alternatives

Chronic pain is defined as pain that is long-term, persisting for longer than 12 weeks or beyond the expected healing time for injuries. It is a common condition, affecting over a third of the adult population. Chronic pain can present itself following injury or due to an underlying condition like arthritis or cancer. However, chronic pain can also occur without a known cause.

Opioids are usually used to manage acute pain in the short term, meaning sudden pain resulting from things like surgery, injury or temporary illness. Although opioids are one of the most effective forms of pain relief, there is not enough evidence to say that opioids are beneficial in the treatment of chronic pain.^1,2 Furthermore, opioids carry the risk of dependence and overdose.³ Despite this, opioid prescriptions under the NHS have increased significantly for chronic pain over the years. 

Hence, many seek alternative pain management techniques, one of which is medical cannabis. Cannabis has been shown to provide pain relief, even in chronic pain, making it a plausible therapy for managing chronic pain in place of opioids.⁴ 

Chronic pain is not just pain

Chronic pain is more than just pain. Pain is an uncomfortable experience of the body and mind, which, when chronic, can lead to other conditions such as:⁵

• Mental health disorders (like depression, anxiety or other mood disorders)
• Suicidal ideation
• Memory problems 
• Problems with sleeping 
• Problems with sexual function

These conditions impact quality of life and can make chronic pain even more painful. 

The problem with using opioids for chronic pain 

Opioid use is a slippery slope. On the one hand, opioids provide great pain relief, work fast and are generally reliable drugs when used sparingly. On the other hand, there is an array of complications associated with these drugs when they are used in the long-term. To understand what makes opioids inappropriate for the management of chronic pain, we must first know how they work and examine the risks associated with opioid use. 

Pain, in simple terms, is excitatory. This means that it is caused by an activation of neurons, which then send signals to the brain for processing and perception. Opioids work by inhibiting neurons via specific receptors; hence, they stop these signals from being picked up in the brain. These specific receptors are not only associated with pain, meaning that opioids have side effects, including:⁶

• Sedation
• Dizziness, nausea and vomiting 
• Constipation
• Slowed or shallow breathing
• Itchiness of the skin
• Physical dependence on the drug
• Tolerance 
• Addiction

Of the listed side effects, some pose more of a clinical threat than others. One of these threats is tolerance, which is an ongoing challenge in the opioid field. With use, opioids can lose their pain relief properties due to the opioid receptors becoming desensitised to the drugs.⁷ This results in the need to keep increasing doses as time goes by, which increases risks of side effects, addiction and overdose. 

Tolerance is associated with physical dependence. Physical dependence occurs when the body gets “used” to a drug, resulting in withdrawal symptoms when it is stopped. Withdrawal symptoms are not only severely uncomfortable, but they also make it harder to stop the drug and make dosing more complicated.⁸

Opioids are also highly addictive. It is estimated that up to 11.5% of patients treated with opioids for chronic pain go on to develop an addiction.⁹ Opioid addiction is considered a severe and chronic mental health disorder, which leads to an array of health and social problems such as breakdowns of interpersonal relationships, crime and death.¹⁰ Continued use of opioids, such as for treatment of persistent conditions like chronic pain, results in a higher chance of addiction. 

It must also be mentioned that those who rely on opioids for chronic pain are at an increased risk of opioid overdose, both intentional and unintentional.¹¹ Overdose of this type of medication is often fatal and is on the rise. 

Medical cannabis and chronic pain

Cannabis remains the most prominently used recreational drug in the UK. Its active chemicals that interact with the body are called cannabinoids. The two main cannabinoids found in cannabis are tetrahydrocannabinol (THC) and cannabidiol (CBD). These substances work to relieve pain by modulating pain sensitisation and also work to decrease inflammation of injured tissue.¹² 

Cannabis has been shown to aid some individuals suffering from certain types of chronic pain, such as neuropathic pain (pain associated with multiple sclerosis, phantom pain or diabetes, among others).^13,14 However, there is not enough evidence to say it is effective for all types of chronic pain, and results vary between individuals.

Reducing opioid reliance with cannabis

Complementary Therapy

Cannabis has been shown to improve the pain-relieving properties of opioids when taken together.¹⁵ This means that using cannabis as a complementary therapy to opioids can potentially reduce opioid doses. Using smaller doses of opioids decreases the risk of addiction and opioid overdose. 

Withdrawal and Tapering

Experimental studies have shown that the THC found in cannabis can actually help in alleviating symptoms of opioid withdrawal.¹⁶ This means that cannabis has the potential to be used in the tapering and discontinuation of opioid therapy. In patients with chronic pain, this would allow for a seamless transition between medications with minimal withdrawal symptoms. 

Initial alternative 

It is known that cannabis can relieve certain types of pain.¹³ For some individuals with chronic pain, it could be beneficial to use cannabis instead of opioids to manage pain symptoms from the get-go. 

Cannabis can also target the consequences of chronic pain, like sleep problems. Cannabis and cannabis-derived products have been shown to help reduce sleep disturbances, hence promoting a better quality of life for some.^17,18 

Benefits of cannabis over opioids

There may be some benefits to using cannabis as an alternative to opioids. Cannabis use poses a significantly lower risk of dependence and accidental overdose and has fewer side effects than opioid use.¹⁹ There has been no documented fatal overdose of cannabis, making dosing easier and safer than opioids.¹⁹ 

Challenges and considerations

It seems that cannabis is a good candidate for the replacement of opioids in chronic pain. However, this is not a one-size-fits-all solution and depends on the individual. 

Limitations of cannabis use in chronic pain

Cannabis has its own side effects, which can alter its effectiveness in this context. For example, cannabis may be effective for pain relief but also increases susceptibility to developing anxiety and mood disorders in some.²⁰ When considering individuals who are already more at risk of developing these disorders, it is imperative that the effect on the individual is considered. 

Limitations of studies 

Studies of pain depend on patient feedback. In conditions like chronic pain, it is difficult to determine whether substances have a significant effect on pain. This is due to other factors potentially skewing the results, for example, the improvement of associated conditions or the placebo effect. 

Summary

Cannabis is a promising alternative therapy to opioids for the management of chronic pain. The reliance on opioids by individuals suffering from chronic pain is on the rise and is risky for a multitude of reasons. These include tolerance, addiction, physical dependence and overdose. 

Cannabis has been shown to have pain-relief properties in specific types of pain, such as chronic neuropathic pain, which is typically associated with multiple sclerosis, diabetes and phantom pain. Cannabis use is safer than opioid use and is associated with a decreased risk of physical dependence, addiction and overdose. Cannabis also has promise in being used as a complementary therapy to opioids to decrease opioid doses and minimise the risk of overdose whilst boosting the pain-relieving effects of opioids. However, the effects of cannabis are dependent on the individual and should be considered case-by-case.