Pharm 101: Metformin
Class
Biguanide
Pharmacodynamics
- Euglycaemic agent
- Reduces hepatic gluconeogenesis by activating enzyme AMPK
- Does not require functioning pancreatic beta cell for its action
Pharmacokinetics
- 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
- Buttner R. Pharm 101: Gliclazide. LITFL
References
- Katzung BG. Basic and Clinical Pharmacology. 14e. 2018: 759-760
Pharmacology 101
Top 200 drugs
Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Co-creator of the LITFL ECG Library. Twitter: @rob_buttner