Is the Environmental Risk of Metformin Underestimated?

摘要

The worldwide prevalence of diabetes mellitus was estimated to be 10.5% in 2021 (536.6 million people) and is expected to increase to 12.2% in 2045.' For many decades, metformin has been the backbone of oral glucose therapy for type 2 diabetes mellitus.2 It is estimated that >150 million people each year take this drug, by far the most prescribed glucose-lowering oral medicine worldwide.3 More recently, metformin has attracted attention because of its capacity to partially prevent long COVID, showing a 42% relative reduction in a placebo-controlled randomized trial.4 Last but not least, this biguanide has also been utilized for the treatment of antipsychotic-induced weight gain, acne vulgaris, polycystic ovarian syndrome, etc.2 The mechanism of action is not fully elucidated, although its therapeutic effects are believed to derive from an insulin-sensitizing action. Hence, due to such widespread use, the large prescribed doses (0.5—2 g/person/ day), and the fact that it is excreted by the kidney primarily unchanged, its routine detection in the aquatic environment comes as no surprise.