The effect of medical cannabis on gastrointestinal symptoms in fibromyalgia and disorders of gut-brain interaction: a patient-centred real-world observational study

Objective Fibromyalgia (FM) is frequently associated with gastrointestinal (GI) disorders such as disorders of gut-brain interaction (DGBIs). Current treatments for FM offer limited relief, leading to the exploration of alternative therapies such as medical cannabis. This study evaluates in the impact of Bedrocan® medical cannabis in FM patients and GI symptoms over six months. Methods Sixty FM patients were enrolled, receiving a Bedrocan® cannabis treatment for 6 months. A standardised questionnaire evaluating upper and lower GI symptoms and the Revised Fibromyalgia Impact Questionnaire (FIQR) evaluating FM severity were administered at enrolment and 3 and 6-month follow-up evaluations. DGBIs, in particular, irritable bowel syndrome (IBS), and functional dyspepsia (FD) were diagnosed according to Rome IV criteria. Results Forty-six/60 (76.6%) FM patients fulfilled the diagnostic criteria for at least one DGBI; 10/60 (16.7%) FM patients fulfilled the diagnostic criteria for IBS, 17/60 (28.3%) for FD, and 19/60 (31.7%) for both IBS/FD. The FIQR severity score log-transformed significantly decreased during the months-by-month comparison period (repeated-measures ANOVA, p<0.001). Among GI symptoms, the log-transformed intensity-frequency score of epigastric pain, epigastric burning, abdominal pain, abdominal distension, and bloating significantly decreased during the month-by-month comparison period (repeated-measures ANOVA, p<0.01). Conclusion This study supports Bedrocan® medical cannabis as an alternative treatment for FM with a potential effect on FD and IBS symptoms. Despite positive outcomes, the study acknowledges limitations, such as the small sample size and absence of a control group. Further research is required to confirm the efficacy of medical cannabis in FM patients, particularly regarding its effects on GI symptoms.