Endometriosis is a chronic inflammatory condition affecting an estimated 6% to 10% of reproductive-age women. It is characterised by endometrial tissue growing outside the uterus, which can lead to chronic pelvic pain, painful periods (dysmenorrhea), and infertility.
Managing the associated pain is often complex. While standard treatments like hormonal therapies and surgery can offer relief, pain persists for many patients. It is in this context that interest in the use of cannabis to address symptoms has grown.
Managing Endometriosis-Related Pain
Pain management for endometriosis can be challenging, as the condition encompasses nociceptive, neuropathic, and nociplastic pain. Conventional interventions for endometriosis include:
- Hormonal therapies: Including combined oral contraceptives, progestogens, and gonadotropin-releasing hormone analogues. While these interventions can provide significant pain relief, pain persists in up to 60% of patients and 20% experience no relief.
- Non-steroidal anti-inflammatory drugs (NSAIDs): Including naproxen and ibuprofen, may provide relief for dysmenorrhoea, but their impact on endometriosis-related pain is unclear.
- Surgery: Excision and ablation surgeries can provide significant pain relief; however, the effects are often temporary, with symptoms recurring in up to three-quarters of women within two years.
- Opioids: In some cases, opioids may be considered as a short-term intervention, but clinical evidence supporting their efficacy for endometriosis-related pain is lacking.
A new scoping systematic review, co-authored by Curaleaf Clinic researchers, analysed the available clinical literature on the use of cannabis in adults with endometriosis to better understand the reported effects and safety profile.
Key Findings from Observational Studies
The review compiled data from nine completed cross-sectional studies, which rely on self-reported patient information, encompassing 1,787 participants.
The primary objective of this literature review was to characterise the observed effects and reported adverse events. The key reported findings from the observational studies included in the review are:
- Most Common Indication: Pain was the most frequent reason reported by participants for using cannabis, ranging from 57.3% to 95.5% of users.
- Other Reported Reasons: Beyond pain, users also reported turning to cannabis for addressing symptoms such as sleep difficulties, gastrointestinal distress, and mood.
- Reported Symptom Relief: Most studies in the review reported that participants stated they experienced an improvement in their symptoms. For example, studies reported that 91.8% of patients using cannabis for pain relief reported improvement.
- Reduction in Other Medications: Several studies reported that participants were able to reduce or completely stop their use of conventional prescribed medications, including non-steroidal anti-inflammatory drugs (NSAIDs), opioids, and anti-anxiety medications. The complete cessation of opioids was reported by up to 31.1% of participants in one study.
- Method and Frequency of Use: Participants most commonly reported using cannabis by inhalation (smoking or vaporising) or ingestion (oils, capsules, or edibles). Between 48% and 70% of respondents reported using cannabis at least once daily.
Reported Adverse Events
The review also detailed the frequency and type of adverse events reported by participants.
Reported adverse events ranged from 10.2% to 52.0% of respondents.
The most frequently reported side effects included “feeling high” (euphoria), a dry mouth, and central nervous system symptoms such as drowsiness.
Some patients reported that they ceased using cannabis due to unwanted side effects.
However, one study reported that 34.7% of cannabis users reported no adverse effects, compared to 2.3% of those using conventional medicines.
The Need for High-Quality Clinical Trials
The review authors noted that while the observational data suggests cannabis may have a role in the management of chronic pelvic pain, the main finding is the paucity of high-quality prospective clinical data.
All completed studies to date are observational and rely on self-reporting, meaning they are susceptible to biases, and it is not possible to definitively conclude whether reported improvements are caused by the cannabis itself or other factors.
The review highlights that there are currently no published Randomised Controlled Trials (RCTs) assessing the use of medical cannabis specifically for endometriosis. Four ongoing RCTs were identified, which are eagerly awaited, as they will help provide more necessary evidence to properly evaluate the safety and efficacy of medical cannabis for endometriosis-associated pain.
Regulated Access in the UK
The UK operates a tightly regulated medical cannabis pathway where products are only available via a prescription from a specialist doctor, ensuring patient safety and product quality.
If you are currently struggling with persistent pelvic pain or are interested in discussing regulated treatment options, the first and most important step is a consultation with a specialist doctor. A specialist can assess your condition, review your medical history, and discuss whether medical cannabis may be a suitable part of your overall care plan.
Curaleaf Clinic provides consultations with specialist doctors to review your individual health needs within the regulated UK framework.