Key Mechanisms of Action

• Reducing hepatic glucose production (gluconeogenesis and glycogenolysis) in the liver.

• Improving insulin sensitivity in peripheral tissues (muscle, adipose tissue), enhancing glucose uptake and utilization.

• Delaying intestinal absorption of glucose and reducing postprandial blood glucose spikes.

• Additionally, it has mild weight-lowering effects and does not cause hypoglycemia when used alone.

Main Uses

1. Type 2 Diabetes Mellitus (Primary Indication)

• First-line therapy for adults with type 2 diabetes, especially those who are overweight or obese, to control fasting and postprandial blood glucose.

• Can be used as monotherapy (for patients with mild to moderate hyperglycemia) or in combination with other antihyperglycemic agents (e.g., sulfonylureas, DPP-4 inhibitors, SGLT-2 inhibitors, insulin) for poorly controlled blood glucose with monotherapy.

• Also approved for pediatric use (children ≥10 years old with type 2 diabetes) in some regions, under medical supervision.

2. Prediabetes

• Used as a preventive intervention in individuals with prediabetes (impaired fasting glucose or impaired glucose tolerance) who have difficulty achieving glycemic control through lifestyle modifications (diet + exercise), to delay the progression to type 2 diabetes.

3. Polycystic Ovary Syndrome (PCOS)

• Off-label use (common in clinical practice): For women with PCOS accompanied by insulin resistance (e.g., hyperinsulinemia, obesity), metformin improves insulin sensitivity, regulates menstrual cycles, and reduces hyperandrogenism symptoms (e.g., hirsutism, acne). It may also improve fertility in some cases by restoring ovulation.

4. Other Potential Applications (Research/Clinical Trials)

• Adjunctive therapy for gestational diabetes (under strict obstetric supervision, as first-line option in some guidelines).

• Potential role in weight management (as an adjunct to lifestyle interventions for obesity, especially in patients with insulin resistance).

• Emerging research on its potential anti-cancer effects (e.g., against colorectal, breast, and pancreatic cancer) and anti-aging properties (still in preclinical/clinical trial stages, not yet approved for these uses).

Important Notes

• Contraindications: Severe renal impairment (eGFR <30 mL/min/1.73m2), acute kidney injury, severe liver disease, metabolic acidosis (including diabetic ketoacidosis), hypersensitivity to metformin, and use of iodinated contrast media (temporarily discontinued before/after contrast administration to avoid lactic acidosis).

• Adverse effects: Common gastrointestinal side effects (nausea, diarrhea, abdominal discomfort) at the start of treatment (usually transient); rare but serious risk of lactic acidosis (more common in patients with renal/hepatic dysfunction or excessive alcohol intake).

• Drug interactions: Avoid concurrent use with drugs that may impair renal function (e.g., NSAIDs) or increase lactic acid levels (e.g., alcohol); adjust dosage when combined with other antihyperglycemic agents to avoid hypoglycemia.