Metformin

Please note: these are basic guidelines, refer to your doctor for a professional medical opinion.

Popular brand names:

Diaphage, Gluconorm, Glucophage, Glucophage XR, Mengen, Metored

Popular combinations:

Galvus Met, Glucovance, Janumet

Drug group:

Drug for diabetes

Prescription needed?

Yes

What does it do?

Metformin is an antidiabetic drug used in the treatment of:

• Type 2 diabetes - used alone, or in combination with  other antidiabetic drugs or insulin
• Insulin resistance and polycystic ovarian syndrome

How does it work?

Metformin reduces blood sugar levels by delaying absorption of glucose and reducing glucose production in the liver. It also helps your body respond better to its own insulin, so that glucose is taken up more effectively from the blood.

How should it be used?

• Management of type 2 diabetes includes an individualized diet and regular exercise
• The drug should be taken with food in order to minimise gastrointestinal side effects

What is the typical dosage?

Your doctor will recommend a dosage tailored to your need, but typically:

Start with low doses, increasing to 1.5–3g daily, taken 2–3 x daily

How quickly will it start to work?

Within 2 hours, full diabetic control may take 2 weeks   
                

How long will the effects last?   

8–12 hours          

When should I stop using it?

Do not stop taking the drug without consulting your doctor.                 

Is it safe for prolonged use?

Prolonged treatment with metformin can lead to:

• Vitamin B12 deficiency - which can rarely cause anaemia
• Potentially fatal build-up of lactic acid in the blood - this usually only occurs in diabetics with impaired kidney function

Regular blood tests for kidney function, blood sugar, and vitamin B12 levels may be required.

What are the possible side effects?

The following have been reported:

• More common: metallic taste in the mouth, minor gastrointestinal symptoms (nausea, vomiting, loss of appetite, diarrhoea)
• Less common: dizziness, confusion, weakness, sweating
• Report to your doctor before taking your next dose if you experience: a rash

What other considerations are important?

Dosage may be adjusted by your doctor under certain conditions.

• Certain health problems: liver/kidney problems, heart failure, alcohol abuse
• Other medicines: corticosteroids, oestrogens, diuretics, monoamine oxidase inhibitors (MAOIs), beta blockers, warfarin
• Pregnancy and breast-feeding: Not usually prescribed in pregnancy - insulin prescribed instead because it provides better diabetic control
• Children: Not recommended under 10 years
• Over 60: Reduced dose may be necessary, increased risk of adverse effects
• Driving and hazardous work: Avoid if you have warning signs of low blood sugar
• Alcohol: Avoid, increased risk of low blood sugar and coma
• Surgery and general anaesthetics: Notify your doctor, insulin may be used instead