Metformin
Metformin is commonly prescribed for type 2 diabetes, often as a first-line medicine alongside diet and physical activity. It may also be used in some other situations as directed by a specialist. Your GP or diabetes team will agree targets and follow-up with you.
This medicine is part of the Diabetes medicines category.
Generic name: metformin
Quick answers
Short replies to searches people often run before speaking to a clinician. For the overview of what the medicine is used for, see the short summary under the page title above.
What is it for?
Metformin is commonly prescribed for type 2 diabetes, often as a first-line medicine alongside diet and physical activity.
How long does it take to work?
Onset varies by condition and dose. Your GP or pharmacist can explain what to expect and when to review.
What are common side effects?
Common effects can include nausea, diarrhoea, stomach cramps, or metallic taste, especially at the start.
Can you take paracetamol or ibuprofen with it?
Ask your GP or pharmacist before taking Metformin with paracetamol or ibuprofen. Many adults use paracetamol for short periods when appropriate; NSAIDs such as ibuprofen need extra checks with your other medicines and health conditions.
More about what Metformin is used for
Metformin is commonly prescribed for type 2 diabetes, often as a first-line medicine alongside diet and physical activity. It may also be used in some other situations as directed by a specialist.
Your GP or diabetes team will agree targets and follow-up with you.
How does Metformin work, and how long does it take to work?
Metformin mainly reduces glucose production by the liver and improves the body’s response to insulin. It does not usually cause low blood sugar when used alone.
It is one part of a broader plan that may include other medicines or insulin if needed.
How and when should you take Metformin?
Metformin is often started at a low dose with meals to limit stomach upset, then increased gradually. Modified-release tablets may be prescribed if standard tablets are poorly tolerated.
Swallow tablets whole unless your prescriber advises otherwise. Follow the schedule you have been given.
What are the common side effects of Metformin?
Common effects can include nausea, diarrhoea, stomach cramps, or metallic taste, especially at the start. These often improve over time.
Taking metformin with food, as advised, can help. Persistent symptoms should be discussed with your GP or pharmacist.
Serious side effects of Metformin — when to get urgent help
A rare but serious condition called lactic acidosis can occur; risk is higher with severe kidney problems, dehydration, or certain other illnesses. Seek urgent care if you become very unwell with deep breathing, severe fatigue, or abdominal pain.
If you are due to have a scan with contrast dye, tell the team you take metformin — they may advise pausing it temporarily.
What if you miss a dose of Metformin?
If you miss a dose, take it with food when you remember unless it is close to the next dose. Do not double the dose.
If you are unsure, your pharmacist can confirm what to do for your tablet type and schedule.
Who should not take Metformin?
Metformin may not be suitable with severe kidney impairment, acute conditions that affect kidneys or hydration, or certain other situations your prescriber will assess.
Always mention liver disease, heart failure, and alcohol use, as these can influence suitability and monitoring.
Can you take paracetamol or ibuprofen with Metformin? — other interactions
Some medicines can affect metformin or kidney function; examples include certain contrast agents and some drugs cleared by the kidneys.
Your prescriber or pharmacist checks combinations; report new prescriptions or over-the-counter purchases.
Metformin in pregnancy and breastfeeding
Diabetes in pregnancy is usually managed with specialist input; metformin may or may not be used depending on individual circumstances.
If you are pregnant, planning pregnancy, or breastfeeding, your GP or specialist will advise on the safest approach.
Blood tests and monitoring on Metformin
Kidney function (eGFR) is typically checked before and during metformin therapy. Vitamin B12 levels may be monitored long term in some people.
HbA1c and other diabetes checks will be arranged as part of routine diabetes care.
What might your GP prescribe instead of Metformin?
Other classes of diabetes medicines (for example, SGLT2 inhibitors, DPP-4 inhibitors, GLP-1 receptor agonists, or insulin) may be added or used instead depending on your needs and heart or kidney health.
Your diabetes team will discuss options in line with NICE pathways where applicable.
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Frequently asked questions about Metformin
People also ask — common Google searches
- What is Metformin used for?
- Metformin is commonly prescribed for type 2 diabetes, often as a first-line medicine alongside diet and physical activity. It may also be used in some other situations as directed by a specialist. Your GP or diabetes team will agree targets and follow-up with you.
- How long does Metformin take to work?
- Onset varies by condition and dose. Your GP or pharmacist can explain what to expect and when to review. Always follow your prescriber’s follow-up plan.
- Can you take Metformin with paracetamol or ibuprofen?
- Ask your GP or pharmacist before taking Metformin with Paracetamol or Ibuprofen. Many adults use paracetamol for short periods when appropriate; NSAIDs such as ibuprofen need extra checks with your other medicines and health conditions.
- What are the side effects of Metformin?
- Common effects can include nausea, diarrhoea, stomach cramps, or metallic taste, especially at the start. These often improve over time. See the sections below for more detail, including serious side effects and when to seek urgent help.
- Will metformin cause hypos?
- When taken alone, metformin rarely causes low blood sugar. Risk increases if it is combined with insulin or certain other diabetes medicines. Your team will explain warning signs if that applies to you.
- Can I drink alcohol with metformin?
- Heavy drinking increases certain risks with metformin. Your GP or pharmacist may advise sensible limits based on your health and other medicines.
Need personalised advice?
Your local pharmacist or GP surgery can help with questions about your medicines, side effects, and alternatives that may be suitable for you.
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Often used with
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