Metformin: A review of its therapeutic efficacy and adverse effects

Managing obesity is a substantial aspect worldwide as well as in diabetic patients. Most oral antidiabetic medications increase body weight. Metformin, the most recommended first-line oral antidiabetic is also considered a weight management agent; however, it has not been approved for this indication. Previous studies have raised doubts on its off-label usage's safety, this review will summarize the effects of metformin on body weight, with special reference to the adverse effects. A literature search on PUBMED was conducted for metformin-related articles in obesity. We included animal experiments, randomized controlled trials and case reports of obese patients with or without type 2 diabetes from any metformin oral dose and reporting useful and undesirable results. Relevant studies from the used references were evaluated. Although metformin may improve weight loss regardless diabetes, it may not confer long-term safety benefits. Metformin showed to induce complications in addition to the gastrointestinal effects, including pancreatitis, hepatitis, vitamin B12 and coagulation abnormalities and reactive hypoglycemia. Our findings suggest to raise patients and healthcare practitioners’ awareness of the long-term risk of metformin when prescribed and dispensed blindly for weight loss purpose.