Metformin

Metformin works by reducing the amount of sugar your liver releases into your blood. It also makes your body respond better to insulin. Insulin is the hormone that controls the level of sugar in your blood.

It's best to take metformin with a meal to reduce the side effects.

The most common side effects are feeling sick, vomiting, diarrhoea, stomach ache and going off your food.

Metformin does not cause weight gain (unlike some other diabetes medicines).

Metformin may also be called by the brand names Bolamyn, Diagemet, Glucient, Glucophage, and Metabet.

Like all medicines, metformin can cause side effects, although not everyone gets them.

Common side effects

Common side effects happen in more than 1 in 100 people. Talk to your doctor or pharmacist if these side effects bother you or don't go away after 1 week:

feeling sick

vomiting

diarrhoea

stomach ache

loss of appetite

a metallic taste in the mouth

Serious side effects

Serious side effects are rare and happen in less than 1 in 10,000 people.

Tell your doctor straight away if you get warning signs of:

a general feeling of discomfort with severe tiredness, fast or shallow breathing, being cold and a slow heartbeat

yellowing of the skin or whites of the eyes - this could be a sign of liver problems

extreme tiredness, lack of energy, pins and needles, a sore and red tongue, mouth ulcers, muscle weakness and disturbed vision - these could be signs of anaemia

a skin rash, redness or itching - this could be a sign of a skin disorder

Serious allergic reaction

In rare cases, it’s possible to have a serious allergic reaction to metformin.