Pharm 101: Metformin



  • Euglycaemic agent
  • Reduces hepatic gluconeogenesis by activating enzyme AMPK
  • Does not require functioning pancreatic beta cell for its action
  • Well absorbed
  • Not protein bound
  • Not metabolised
  • Half-life 1.5-3 hours
  • Excreted by kidney as unchanged compound
Clinical uses
  • Diabetes mellitus
Adverse effects
  • GI upset in 20%, limits compliance with drug
  • HAGMA (lactic acidosis), especially in patients with coexistent renal failure, alcoholism, chronic cardiopulmonary disease
    • Contraindicated if eGFR < 30 ml/min
  • Decreased B12 absorption
Further reading

Pharmacology 101

Top 200 drugs

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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