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What does it do?

Metformin is used to treat diabetes, and sometimes other conditions.

Before you start

  • Tell your doctor if you have kidney problems.
  • Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.

How should you take it?

Take metformin regularly as directed with a glass of water.

What if you forget a dose?

If it is nearly time for your next dose, skip the missed dose and take your next dose at the usual time. Otherwise, take the missed dose as soon as you remember. Do not take two doses at the same time.

Can you take other medicines?

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products or recreational drugs.

What side effects might you notice?

Side EffectsRecommended action

Symptoms of a very rare but serious problem called lactic acidosis including: nausea, vomiting, diarrhoea, weakness, muscle pain, fast breathing

Tell your doctor immediately

Changes in taste, loss of appetite

Tell your doctor if troublesome

Stomach upset, farting, indigestion

Common when you first start but should improve. Tell your doctor if troublesome.

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

  • You will need a regular blood test (HbA1c) to check how your diabetes is controlled.
  • If you are unwell, follow your diabetes sick-day plan, or talk to your health professional.

This leaflet contains important, but not all, information about this medicine.

Prepared by the MyMedicines Committee at Christchurch Hospital, Te Whatu Ora - Waitaha, New Zealand. November 2024

For more general information about this sheet and its contents, see: What does a My Medicines sheet cover?

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About My Medicines

My Medicines Patient Information Leaflets (PILs) contain important, but not all, information about the medicines they describe.

For more information about the sheets, see: What does a My Medicines sheet cover?

My Medicines is developed by a team at Te Whatu Ora – Waitaha. Our team is made up of doctors, pharmacists, and a non-medical person to help us keep to plain language. We also discuss our information with specialist health professionals or groups when needed