In recent years, the global cannabidiol (CBD) industry has grown at an incredible rate, largely thanks to a shift towards natural “wellness” products. CBD products, widely touted as a remedy to various ailments or as an aid to general health and wellness, can now be purchased in pharmacies, supermarkets, and online in the UK and many other countries around the world. However, whilst the use of CBD products which do not meet pharmaceutical standards continues to increase, do these products represent hope for patients or is it all hype?
In 2021, the International Association for the Study of Pain issued a position statement concluding that due to a lack of evidence from high-quality research, it did not endorse the general use of cannabinoids to treat pain. In the UK, also in 2021, the National Institute of Health and Care Excellence (NICE) reported that there is evidence to suggest cannabis-based medicinal products were clinically effective, but not cost-effective for wider prescribing on the NHS. Other evidence reviews are more positive, suggesting that non-inhaled medical cannabis products are associated with a small improvement in pain severity, leading to recommendations that these should be considered when first-line therapies have proven ineffective. The general consensus on medical cannabis products is that there needs to be more high-quality evidence to support its effectiveness before it can be considered earlier in the treatment pathway for chronic pain.
In contrast to medical cannabis, non-pharmaceutical preparations of CBD do not have to meet the same stringent standards to ensure its quality and consistency. The FSA previously analysed a selection of CBD products on sale in England and Wales. Of 6 food and drink products claiming to contain CBD, half contained less than the declared amount, with 1 (16.7%) product containing no CBD at all. 2 (8.7%) out of 23 oils analysed contained substantially different quantities of CBD compared to the declared amount on the packaging. In addition 87% of all samples were found to contain THC, with 40% containing above the legal threshold. This indicates that most wellness products are not even able to meet the less stringent regulations.
A recent review article aimed to assess current evidence to better understand the safety and efficacy of CBD for pain.
Methods of the Study
The authors systematically searched research databases for information and studies relating to the analysis of CBD products, their purity, and the presence of contaminants, and for any associated harms with their use. In addition, they identified completed randomised, double-blind trials comparing CBD with placebo since 2019.
They then analysed pain outcomes at any time point, for any painful condition, using any CBD product, at any dose, and by any route of administration.
CBD For Pain – Results of the Study
Non-Prescription CBD
Consumer CBD or over-the-counter CBD refers to products that are sold commercially, such as in specialist shops, pharmacies or online, without the need for a prescription. These products are most commonly derived from the hemp plant – a type of cannabis that contains extremely small amounts of the psychoactive compound THC. Such products are extremely popular in Europe and North America. A lack of regulations means that the quality and contents of some products may be questionable. For example, in an analysis of topical CBD products in the US, THC was detected in 35%, with a total content of up to 100 mg.
Similar disparities have previously been seen in some European countries and the UK as highlighted.
Pharmaceutical Grade CBD for Pain
The researchers identified 16 clinical trials of CBD for various types of pain. The trials were conducted in 12 different pain conditions, using three routes of administration (10 oral, 3 topical, and 3 sublingual), with different CBD doses between 6 and 1,600 mg, and different durations of treatment (ranging from a single dose to 12 weeks).
Eleven trials were able to be included in a pooled analysis. Ten of these 11 trials showed that CBD produced little or no pain relief, with no statistical or clinically significant difference between CBD and placebo for either trial design. A further parallel-group trial and 4 crossover trials which didn’t provide pooled analysis also showed no difference between CBD and placebo. However, a trial of 18 patients with symptomatic basal joint arthritis did show that topical CBD was associated with improvements in pain over a two-week treatment compared with placebo (mild pain with CBD vs moderate/severe pain with placebo).
Again the issue with this data is the quality of trials included in the review. The quality of the review is heavily dependent upon the quality of original research, which in this case was lacking. Many studies included small sample sizes, with many also considering pain conditions for which medical cannabis is not commonly prescribed.
Pharmaceutical Grade CBD – Safety
Many patients with pain may be interested in cannabis-based medicines as a safer alternative to other medications, such as opioids and other strong painkillers, many of which possess a significant risk of addiction and overdose. However, while the World Health Organisation has concluded that, in its pure form, “cannabidiol does not appear to have abuse potential or cause harm”, it should be noted that the cannabinoid is often associated with more adverse events than placebo.
For example, a meta-analysis for epilepsy found that 9.7% of patients treated with CBD had at least one adverse event, twice the rate for placebo. Moreover, another study indicates that around 7% of patients may be affected by CBD-related hepatotoxicity, with elevated liver enzymes.
Conclusions
Dr Simon Erridge, Research Director at Curaleaf Clinic, provided the following overview of the study for this blog:
“This study aims to summarise the effects of CBD-only therapy on pain. Whilst arriving at a conclusion that CBD does not work for chronic pain. I believe this is short-sighted and rather the conclusion should be that there is insufficient high-quality evidence to determine the effectiveness of CBD in chronic pain.
The included studies are small in size and 81% of included studies in the meta-analysis follow-up participants for 4 weeks or less.
Finally, the included studies assess the outcomes in acute pain or indigestion, conditions for which medical cannabis would not even be considered in the UK.
The authors highlight the burden that chronic pain can cause patients and how this makes them vulnerable to the claims of non-pharmaceutical CBD products. For patients who have reached this point, it would be more appropriate for them to see a pain specialist at a clinic, such as Curaleaf, to determine if they are suitable for medical cannabis and if so which product is most appropriate for them.”
