Efficacy, tolerability, and safety of cannabinoids in gastroenterology: A systematic review

Background: The medical use of cannabis is discussed in gastroenterology for inflammatory bowel diseases (IBD), irritable bowel syndrome (IBS), and chronic pancreatitis. Materials And Methods: A systematic literature search until March 2015 was performed in the databases Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, www.cannabis-med.org , and clinicaltrials.gov. Randomized controlled trials (RCT) investigating herbal cannabis and/or pharmaceutical cannabinoids in IBD, IBS, or chronic pancreatitis with a study duration of >/= 4 weeks and a sample size of at least n = 10 per study arm were identified. Clinical outcomes comprised efficacy (pain, nausea, appetite/weight, diarrhea, health-related quality of life, and remission rates for IBD), tolerability (drop-out rate due to side effects), and safety (severe side effects). Methodology quality of RCTs was evaluated with the Cochrane Risk of Bias Tool. Results: Only one RCT treating 21 patients with Crohn's disease and herbal cannabis was identified. The study revealed no significant differences of remission rate because of low statistical power. However, there was a clear tendency for less abdominal pain and improved appetite with medical cannabis. The methodological risk of the study was high. Furthermore, results of two RCTs investigating synthetic cannabis in IBD and chronic pancreatitis, respectively, have not yet been released. No RCT for IBS was found. Several case reports described cannabis-induced acute pancreatitis. Conclusions: Cannabis may be useful for symptom relief in Crohn's disease such as pain, nausea, and loss of appetite. However, studies with high methodological quality, sufficient sample size, and study duration are mandatory to determine potential therapeutic effects and risks of cannabis in gastroenterology. Currently, use of tetrahydrocannabinol to alleviate symptoms such as pain and appetite loss in Crohn's disease should only be considered in individual patients after failure of established medical therapies and only after careful risk-benefit assessment.