The use of melatonin in the treatment of irritable bowel syndrome: a systematic review of randomized placebo-controlled clinical trials

Introduction. One of the most prevalent functional disorders of the gastrointestinal system, irritable bowel syndrome (IBS), significantly affects patients’ quality of life. At the moment, only symptomatic drugs are used to treat this disorder. Although using melatonin can be thought of as a form of pathogenetic therapy, its efficacy has not yet been conclusively demonstrated. This systematic review of randomized placebo controlled clinical trials reviews current data on the evaluation of the efficacy of melatonin in patients with IBS. Material and research methods. The search and selection of publications was carried out in the PubMed, ScienceDirect, ClinicalTrials.gov, Cochrane Library, eLibrary, medRxiv and International Clinical Trials Registry Platform databases from their publication until October 30, 2022. Results. The inclusion criteria were met by four randomized placebo-controlled trials, totaling 155 participants, and these trials were included in the subsequent analysis. All investigations revealed a considerable reduction in the frequency and severity of bloating, as well as a tendency for other intestinal symptoms to regress. Two trials reported an improvement in patients’ quality of life, albeit one of the studies did not find these changes to be statistically significant, and the other did not assess them. This review demonstrates that melatonin is effective in treating IBS by lowering the frequency and severity of the condition’s symptoms in the vast majority of published RCTs. The poor number and sample size of clinical trials, along with their inadequate methodological quality, prevent us from drawing any firm conclusions about the contribution of melatonin to the improvement of IBS patients’ quality of life. To confirm melatonin’s significance in the treatment of IBS patients, larger studies are required to assess its efficacy and safety when used in various doses.