Cannabis-Based Medicinal Products for Endometriosis: A 2-Year Prospective Analysis from the UK Medical Cannabis Registry.

BACKGROUND:Endometriosis affects up to 10% of biological females of reproductive age. Current treatment options are limited and often unsuitable for prolonged use. Cannabis-based medicinal products (CBMPs) have emerged as an alternative for pain management. AIMS:To analyse changes in patient-reported outcome measures (PrOMs), prescribed opioid burden, and the prevalence of adverse events (AEs) in patients prescribed CBMPs for endometriosis-associated pain. MATERIALS AND METHODS:This was an observational analysis of prospectively collected data from the UK Medical Cannabis Registry. Biological females (≥ 18 years) with a primary diagnosis of endometriosis, enrolled ≥ 2 years prior to data extraction on 06/01/2025, were included. PrOMs and prescribed oral morphine equivalents (OME) were assessed between baseline and 1, 3, 6, 12, 18, and 24 months. Changes from baseline were assessed by repeated-measures ANOVA and Bonferroni-adjusted post hoc pairwise t-tests. p < 0.050 was considered statistically significant. RESULTS:One hundred and one patients were included. Improvements from baseline were observed in BPI Severity, BPI Interference, SF-MPQ-2 Total, Pain VAS, EQ-5D-5L Index, GAD-7, and SQS at all follow-ups (p < 0.001). Mean prescribed OME decreased from 19.9 ± 17.2 mg/day at baseline to 14.8 ± 15.9 mg/day at 24 months. Eighteen participants (17.8%) reported 165 AEs, of which 84 (50.9%) were mild. The most frequent were fatigue (n = 16; 15.8%), lethargy (n = 15; 14.9%), and headache (n = 13; 12.9%). CONCLUSION:CBMP treatment was associated with sustained improvements in pain, health-related quality of life, sleep, and anxiety at 24 months, with a favourable AE profile. Randomised controlled trials are required to establish efficacy and safety.