Abstract：
Metformin is the first-line medication for type 2 diabetes. It is effective and safe, provided some caution is taken in specific populations. In patients with chronic kidney disease, metformin may provide long-term benefits, and it is a first-line therapy for diabetes, but the estimated glomerular filtration rate (eGFR) must be assessed regularly, to minimize the risk for metformin accumulation. When eGFR is 30-60 mL/min/1.73m2, the dose should be reconsidered, and sick-days education provided. Metformin should be discontinued when eGFR falls below 30 mL/min/1.73m2. Metformin accumulation may increase the risk for lactic acidosis if concomitant risk factors for hyperlactataemia (liver or respiratory insufficiency, sepsis, acute heart failure) are present; in these conditions, metformin is contraindicated, even although the available evidence is reassuring. Patients on metformin often complain of gastrointestinal side effects (mainly diarrhoea and nausea) during therapy initiation, but they may sometimes occur after years of stable therapy. These usually resolve if the dose is carefully titrated, or by switching to the extended-release formulation. Patients with obesity may benefit from the significant, although modest, metformin-associated weight loss and appetite reduction. During pregnancy, metformin is associated with a reduction of pregnancy complications, especially in obese women, but some concern remains, because metformin crosses the placenta, and it is associated with a significantly lower mean birth weight than insulin. In the elderly, gastrointestinal tolerability and renal function must be reassessed more often. Vitamin B-12 should be screened regularly in long-time metformin users because metformin may induce clinical vitamin B-12 deficiency.
摘要：
二甲双胍是治疗2型糖尿病的一线药物。它既有效又安全，前提是在特定人群中采取一些谨慎的态度。慢性肾病患者,二甲双胍可能提供长期益处，它是糖尿病的一线疗法，但是估计的肾小球滤过率（eGFR）必须定期评估，降低二甲双胍积累的风险。当eGFR为30-60mL/min/1.73m2时，应重新考虑剂量，并提供病假教育。当eGFR低于30mL/min/1.73mL时，应停用二甲双胍。如果伴随高乳酸血症的危险因素（肝脏或呼吸功能不全，脓毒症,急性心力衰竭）存在；在这些情况下，二甲双胍是禁忌的，即使现有的证据令人放心。服用二甲双胍的患者在开始治疗期间经常抱怨胃肠道副作用（主要是腹泻和恶心）。但它们有时可能在经过多年的稳定治疗后发生。如果仔细滴定剂量，这些通常会解决，或通过切换到延长释放制剂。肥胖患者可能受益于显著，虽然谦虚，二甲双胍相关的体重减轻和食欲减少。在怀孕期间,二甲双胍与妊娠并发症的减少有关，尤其是肥胖女性，但仍有一些担忧,因为二甲双胍穿过胎盘,它与平均出生体重明显低于胰岛素有关。在老年人中,必须更频繁地重新评估胃肠道耐受性和肾功能。长期服用二甲双胍的患者应定期筛查维生素B-12，因为二甲双胍可能导致临床维生素B-12缺乏。
