We encounter metformin almost every day in practice — in patients’ medication list / we prescribe to patients / we withhold for patients. It is very important to understand the medications that we are giving, so that we do no harm to patients.
1️⃣ Mechanism of action
- Reduce insulin resistance
- Reduce gluconeogenesis
2️⃣ Therapeutic effects / Benefits
- Reduce HbA1c by 1.5%
- Low risk of hypoglycaemia
- Synergistic effect when combined with other oral antidiabetic agents
3️⃣ Side effects
- Gastrointestinal disturbance: nausea, anorexia, diarrhoea (usually transient)
- Lactic acidosis, especially renal impairment / acute illness that predisposed to lactic acidosis
4️⃣ How to start T Metformin?
- Initially low dose: T Metformin 500 mg OD/BD, may titrate up weekly to 1g BD for further glycaemic control if patient able to tolerate
5️⃣ When to stop metformin?
- Serum creatinine >150 µmol/L, OR
- eGFR <30 mL/min, OR
- Acute illness (that predisposed to reduced drug elimination / dehydration -> lactic acidosis) e.g. sepsis, shock, AKI, transaminitis/liver failure/hepatitis
6️⃣ Further reading
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3114336/
