Medication Information Leaflet

What is this medication for?

Metformin controls diabetes by helping your body to use insulin better. It also decreases the amount of sugar made by your liver, therefore reducing your sugar levels in the blood.

How should I take/use this medication?

Take with or after food. This lowers the chance of getting stomach discomfort, nausea and diarrhea.

What should I do if I forget to take/use this medication?

If you miss a dose, take the missed dose as soon as you remember. Remember to take it with food. If it is almost time for your next dose, take only the usual dose. Do not double your dose or use extra medication to make up for the missed dose.

What precautions should I take?

Inform your doctor if 

  • you are allergic to this medication or any of the other ingredients of this medication
  • you are pregnant, planning to become pregnant, or breastfeeding
  • you have a heart condition, kidney or liver problem
  • you drink alcohol often
  • you are going for a scan/ X-ray. You may need to stop taking metformin for a couple of days
If you need to do fasting blood tests, do not take your medication until your blood has been taken and you have eaten.

What are some common side-effects of this medication?

It may cause stomach discomfort, nausea, vomiting, diarrhea, loss of appetite and metallic taste in your mouth. These symptoms should get better over time. Check with your doctor if any of these symptoms are serious or do not go away. Taking metformin after food or with food may help to reduce some of these symptoms.

What are some rare but serious side-effects that I need to seek medical advice immediately?

Lactic acidosis (a buildup of lactic acid in the body) is a very rare but serious medical problem. The chance of this happening increases if your kidneys are not working properly.

Symptoms of lactic acidosis include 

  • decreased appetite
  • vomiting and stomach pains that continues for some time
  • a general feeling of  being unwell accompanied with feeling cold or excessive tiredness
  • fast, shallow breathing.
If any of these happens, stop taking your medication and see a doctor immediately as you will need treatment straight away.

What food or medication should I avoid when I take this medication?

Avoid taking alcohol when you are on medication as it increases the risk of lactic acid buildup in your body.

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How should I dispose of this medication safely?

Pack this medicine into a black trash bag and seal it tightly before throwing into the rubbish chute or bin.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore.

Last updated on May 2019


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