METFORMIN, ORAL

Metformin, oral, 500 mg twice daily with meals.
- Titrate dose slowly depending on HbA1c and/or fasting blood glucose levels to a maximum dose of 850 mg 8 hourly.
- Monitor renal function.
- Dose-adjust in renal impairment as follows:
  - eGFR > 60 mL/minute: Normal daily dose (see above).
  - eGFR < 60 mL/minute: Half of the daily dose.
  - eGFR < 30 mL/minute: Stop metformin.
- Contra-indicated in:
  - renal impairment i.e. eGFR < 30 mL/minute,
  - uncontrolled congestive cardiac failure,
  - severe liver disease,
  - patients with significant respiratory compromise, or
  - peri-operative cases.
- Drug-drug interaction with dolutegravir (DTG): DTG may increase the serum concentration of metformin. Limit maximum dose of metformin to 1000 mg daily if concomitant use with DTG.