Metformin for diabetes

Sounds like 'met-for-min'

Key points about metformin for diabetes

Metformin is used to treat and prevent type 2 diabetes.
Metformin lowers your blood glucose levels and reduces your risk of having a heart attack or stroke.
Find out how to take it safely and possible side effects.

Metformin is a tablet used to treat or prevent type 2 diabetes. It's usually the medicine of first choice for this condition. Metformin lowers your blood glucose levels and your chance of having a heart attack or stroke. It has other benefits such as mild weight loss. Read more about type 2 diabetes and pre-diabetes.

Metformin may be used to treat gestational diabetes (diabetes that develops during pregnancy). Read more about gestational diabetes and taking metformin for gestational diabetes(external link) (te reo Māori(external link) and Samoan(external link)).

Metformin is also used to treat polycystic ovarian syndrome.

Metformin can be used alone or in combination with other medicines such as insulin. It's available with vildagliptin (then called Galvumet) or empagliflozin (then called Jardiamet).

In Aotearoa New Zealand, metformin is only available with a prescription written by a prescriber.

In Aotearoa New Zealand, metformin is available as tablets (500 mg and 850 mg).

The usual starting dose for adults with diabetes is 500 mg once or twice a day. Depending on your blood glucose levels, your healthcare provider may increase your dose slowly over a few weeks. This allows your body to get used to the medicine and reduces side effects.
The maximum dose is 3 grams daily (in divided doses) but for some people, such as older adults or people with kidney problems, the maximum daily dose should be lower.
Always take your metformin exactly as your healthcare provider has told you. The pharmacy label on your medicine will tell you how much metformin to take, how often to take it and any special instructions.

Take them whole: Swallow your tablets whole with a drink of water.
Timing: Each day's tablets are usually divided into 2 doses (breakfast and dinner), or sometimes 3 doses (breakfast, lunch and dinner). Try to take your metformin dose at the same times each day, to help you remember to take it.
Food: Always take metformin with food – during a meal or just after a meal. This helps to reduce side effects.
Missed dose: If you forget to take your dose, take it (with food) as soon as you remember. But if it's nearly time for your next dose, just take the next dose at the right time. Don't take double the dose.

Here are some things to know when you're taking metformin. Other things may be important as well, so ask your healthcare provider what you should know about.

Alcohol: Limit alcohol while taking metformin. Having the occasional drink while you're taking metformin is safe. However, regularly drinking excessive amounts increases your chance of side effects and reduces the effects of metformin. Read more about diabetes and alcohol.
Keep taking metformin regularly: To control your diabetes you must take metformin every day. Treatment for diabetes is usually lifelong. Don’t stop taking metformin without talking to your healthcare provider first.
Metformin and vitamin B12: Diabetes and long-term metformin can both cause low levels of vitamin B12. You may need to have a blood test to check vitamin B12 if you have symptoms of anaemia (fatigue, dizziness, mouth ulcers), and you may need to take a supplement for this.
Other medicines or supplements: Metformin can interact with some medicines, herbal supplements and rongoā Māori, so check with your healthcare provider or pharmacist before starting metformin and before starting any new products.
Surgery: You may need to stop taking metformin before having major surgery and some medical tests. Let your healthcare team know that you're taking metformin.
Unwell from vomiting (being sick) or diarrhoea (runny poo): If you have severe tummy problems (eg, vomiting or diarrhoea lasting more than a few hours) and you're possibly getting dehydrated, ask your healthcare provider for advice. They may recommend you stop taking metformin until you're better. Read more about a sick day plan for people with type 2 diabetes.
Monitoring: You’ll have regular blood tests to check how well your metformin is working.
Pregnancy or breastfeeding: Talk to your healthcare provider if you're pregnant, planning a pregnancy or want to breastfeed.

Side effects with metformin are rare. Like all medicines, metformin can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Side effects	What should I do?
Feeling sick (nausea) Diarrhoea (runny poo) Stomach upset and bloating	These are common when you first start taking metformin and usually go away with time. Take your metformin with food. Tell your healthcare provider or pharmacist if these bother you.
Changes in taste	Let your healthcare provider know if this bothers you.
Signs of low blood glucose (hypoglycaemia) such as feeling weak, faint, dizzy or irritable. You may get a headache, tremor (shakes) or blurred vision.	If you’re taking metformin with other medicines for diabetes, there is a very rare chance that your blood glucose can be lowered too much. If this happens, drink something sweet such as a small glass of sweetened soft drink or fruit juice, or eat something sweet such as lollies. Follow this up with a snack such as a sandwich. Read more about hypoglycaemia. Tell your healthcare provider if this happens.
Symptoms of lactic acidosis such as drowsiness, stomach cramps, vomiting (being sick), muscle pain	Metformin can very rarely cause a condition called lactic acidosis. You're at highest risk if you have kidney problems, a severe infection, dehydration, heart failure or drink a lot of alcohol. To avoid this, your healthcare provider will monitor how well your kidneys are working and adjust your metformin dose accordingly. Your healthcare provider may stop your metformin for a short time if you become dehydrated or have severe diarrhoea (runny poo), a severe infection or you're having surgery or an X-ray where a dye is needed. Let your healthcare provider know or call Healthline 0800 611 116.
Signs of an allergic reaction such as skin rash, itches, swelling of the face, lips, mouth and tongue or problems breathing	This is rare. Stop taking metformin and phone 111 for an ambulance.