About metformin hydrochloride
Biguanide antidiabetic medicine
Used for
- Type 2 diabetes, alongside diet and exercise
- Sometimes used for polycystic ovary syndrome
Usual adult dose
Usually starts at 500 mg once or twice daily with meals; increased gradually as needed. Dose depends on the formulation.
Usual dose in children
For type 2 diabetes from age 10: usually 500 mg once or twice daily with meals; increased gradually as needed.
Common side effects
- Nausea, diarrhoea, stomach discomfort, or reduced appetite
- Metallic taste
- Vitamin B12 deficiency with long-term use
Important warnings
- Rarely, can cause life-threatening lactic acidosis, especially with severe kidney problems or serious illness.
- Kidney function should be checked; avoid in severe kidney impairment.
- Temporary interruption may be needed around certain scans using contrast dye or major surgery.
- Long-term use can lower vitamin B12 levels.
Pregnancy
Use during pregnancy requires clinician review; insulin is often preferred for diabetes management.
Breastfeeding
Passes into breast milk in small amounts. Use requires clinician review, especially for newborn or premature infants.
Interactions
- Iodinated contrast dye may require temporary interruption.
- Some medicines, including cimetidine and certain diuretics, can increase metformin levels.
- Alcohol increases the risk of lactic acidosis.
- Insulin and sulfonylureas can increase low blood sugar risk.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.