medicinal cannabis fibromyalgia in chronic pain patients

A Study of the Effects of Medicinal Cannabis on Chronic Pain in Fibromyalgia

Fibromyalgia is the second most common rheumatologic condition and it is estimated that it affects around 1.5-2 million people in the UK alone. Yet the causes of the condition are still not completely understood. Patients of Fibromyalgia can experience a number of symptoms, however, the most common is feelings of chronic pain and fatigue around the body.

As little is understood about what causes Fibromyalgia, there is no cure for the condition. However, there is a range of treatments that are aimed at making symptoms more manageable. These can include exercise programmes, Cognitive Behavioural Therapies, and medicines such as antidepressants and painkillers.

The condition is also often accompanied by secondary symptoms including sleep disturbance,  tiredness, and cognitive symptoms such as memory deficits.

Could Medical Cannabis Help in the Treatment of Fibromyalgia?

Cannabis has been used medicinally for thousands of years thanks to the properties of a number of compounds within the plant. The most promising, and most common, of these compounds, there are cannabinoids which have been shown to interact with important receptors within our bodies. The Endocannabinoid System is thought to modulate several processes including pain, temperature, and mood.

There is a large amount of anecdotal evidence highlighting the potential of cannabis to improve symptoms of pain conditions such as Fibromyalgia. In addition, several clinical studies have explored the potential of cannabis as a treatment option in recent years.

What is the Evidence?

One recent study, published in 2019, studied the analgesic effects of pharmaceutical-grade cannabis in chronic pain patients with Fibromyalgia. For the study, a total of 20 patients were assessed in a placebo-controlled 4-way crossover trial. Three different varieties of medical cannabis with differing levels of Tetrahydrocannabinol (THC) and Cannabidiol (CBD) – Bedrocan, Bediol, and Bedrolite – as well as one placebo variety without any THC or CBD.

The study assessed various forms of pain relief in response to the different varieties of cannabis. Experimental pressure pain, electrical pain, and spontaneous pain were measured through a developed scoring system which was measured before and after the application of each compound. In addition, researchers also assessed subjective and psychotropic effects.

The Effect on Pain Ratings

The study found that patients given a cannabis variety (Bediol) containing 13.4mg THC and 17.8mg CBD were more likely to experience at least a 30% decrease in pain scores compared to placebo. In addition, pressure pain threshold was found to be increased in patients treated with Bedrocan and Bediol – the two cannabis varieties with a high THC content.

However, Bedrolite – a variety with high CBD content – did not have an effect on spontaneous and evoked pain models. Although CBD increased the plasma concentrations of THC, it also produced an opposite effect on the pain relief induced by THC according to the study authors.

The Side Effects

Researchers also assessed various effects of the cannabis varieties. This included the measurement of euphoria, alterations in internal and external perception, and alertness/drowsiness. These factors were measured using validated patient questionnaires.

All three of the active cannabis varieties caused higher euphoria responses than placebo. The reduction seen in spontaneous pain scores was seen to be correlated with the concentration of THC. Other side effects of treatment included drowsiness and nausea. A majority of participants also experienced sore throat, bad taste, and coughing during the vapour administration of the active varieties.

This study cautiously outlines the potential of cannabinoids in the treatment of pain associated with Fibromyalgia. It concludes that THC appears to be the main analgesic compound associated with cannabis yet advises more research to be carried out in this area.