Boots WebMD Partners in Health
Return To Boots

Diabetes health centre

Select An Article

Coping with the side effects of metformin

Metformin is prescribed for some people with diabetes to help keep their blood sugar levels under control.

Metformin works by encouraging the body to burn energy, leading to lower blood glucose levels. If you take metformin it is usually more effective at lowering blood glucose levels than if you are just careful about what you eat.

Nausea

Metformin has a number of side effects, the most common of which are gastrointestinal.

More than one in 10 people who take metformin experience side effects including nausea, vomiting, diarrhoea, stomach pain, increased flatulence or loss of appetite.

More than one in 100 patients who take the medication experience changes to their sense of taste - usually a metallic taste.

A number of other very rare symptoms have also been reported. Fewer than one in 10,000 people who take metformin may experience:

  • Abnormal laboratory test results
  • A dangerous build-up of lactic acid ( lactic acidosis) which can lead to coma
  • Liver problems
  • Skin problems such as erythema, itching or urticaria
  • Vitamin B12 levels reduced when metformin is taken over a long period

What to do about side effects

All medications take some getting used to. The NHS advises that patients can avoid the more common gastrointestinal side effects by taking the medication during or after a meal.

In order to guard against vitamin B12 deficiency - which in rare cases becomes apparent in patients who have taken the medication for a long time - the charity Diabetes UK recommends eating a healthy, balanced diet including foods rich in vitamin B12 such as meat, dairy products and eggs.

However, it is not recommended for those prescribed metformin to also take vitamin B12 supplements unless advised to by their doctor.

Patients who feel unwell or who are concerned about a side effect should talk to their GP, pharmacist or practice nurse. Immediate medical attention should be sought in cases of breathing difficulties, muscle cramps, stomach pain, weakness or hypothermia, which can be symptoms of lactic acidosis.

Next Article:

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on May 24, 2017

Diabetes newsletter

Tips for managing your diabetes.
Sign Up Now!

Popular slideshows & tools on BootsWebMD

woman_holding_head_in_pain
How to help headache pain
rash on skin
Top eczema triggers to avoid
79x79_causes_of_fatigue_and_how_to_fight_it.jpg
Causes of fatigue & how to fight it
period_questions_answered
Tips to support digestive health
woman looking at pregnancy test
Is your body ready for pregnancy?
woman sleeping
Sleep better tonight
girl_sneezing_into_tissue
Treating your child's cold or fever
bucket with cleaning supplies in it
Cleaning and organising tips
adult man contemplating
When illness makes it hard to eat
woman holding stomach
Understand this common condition
cold sore
What you need to know