Glucophage (metformin) is usually taken with meals or right after eating. Doctors often start with a low dose and raise it gradually to reduce stomach upset. The most common side effects are nausea, diarrhoea and stomach cramps, which usually ease within weeks. Long-term use may cause vitamin B12 deficiency, so it is checked regularly. Do not change your dose or stop the medicine on your own, and talk to your doctor before any surgery or imaging dye.
What Is Glucophage and Why Do Doctors Prescribe It?
Glucophage is the brand name for metformin, which belongs to a drug class called biguanides [2]. It is used to treat type 2 diabetes, alone or with other medicines, including insulin [2]. It helps control blood sugar by reducing how much glucose the body absorbs from food and how much the liver produces, and by improving the body's response to insulin [2].
The UK's National Health Service (NHS) lists other uses, including gestational diabetes and the symptoms of polycystic ovary syndrome, and notes that it is available only on prescription [1]. You can read product information on the Glucophage (Metformin) page and the Glucophage XR page, and find a simple explanation in the Metformin glossary entry.
The medicine alone is not enough. Healthy eating, physical activity and quitting smoking remain part of the plan even when taking diabetes medicines [3]. It controls diabetes but does not cure it [2].
How Is Glucophage Taken? Correct Usage
The dose depends on the reason for use and on age, and it is recommended to take it with food. Most people take it once to three times a day, and the doctor may prescribe a lower dose at the start [1]. The usual dose is set by your doctor or pharmacist, and you should not increase or decrease it on your own. Always follow what is written on your box and leaflet [1].
| Form | Usual Timing | Important Notes |
|---|---|---|
| Regular tablet (e.g. Glucophage 500mg) | With meals, two or three times a day [2] | Swallow whole with a little water; do not crush or chew [1] |
| Extended-release tablet XR (e.g. Glucophage XR 750mg) | Once daily with the evening meal [2] | Swallow whole; do not split, chew or crush [2] |
| Solution or powder (depending on availability) | With meals, once or twice daily for the solution [2] | Measure the solution with the spoon or syringe provided; mix the powder with 150 ml of water [1] |
Starting Low and Increasing Gradually
Your doctor may start with a small dose and increase it gradually, with no more than one increase every one to two weeks [2]. This gradual approach gives the stomach time to adjust. You will also need to check your blood sugar as your doctor advises, so they can see how well the medicine is working [2].
Practical Daily Tips
- Take it at the same times each day to make it easier to stay consistent [2].
- You can eat your usual food, but follow a healthy diet set by your doctor or dietitian [1] [2].
- Continue taking the medicine even if you feel better, because stopping it may cause blood sugar to rise again [1] [2].
- With XR tablets, you may see something resembling a tablet in your stool. This is only the empty shell and does not mean your dose was not absorbed [2].
- Children aged 10 years and older may take it according to the NHS [1], but their dose is based on weight and must be prescribed by a doctor or guided by a pharmacist.
What Should I Do If I Miss a Dose or Take Too Much?
If you take it once a day and forget a dose, take it as soon as you remember, unless the next dose is almost due. If you take it more than once a day and the next dose is close, skip the missed dose and continue with your usual schedule [1]. Never double a dose to make up for a missed one [1] [2]. For more detail, read What should I do if I miss a dose of diabetes medication?
Taking an extra dose can be dangerous [1]. If you have taken more than prescribed, call 911 or go to the nearest emergency department, and bring the medicine box, the leaflet and any other medicines you are taking [1]. Do not drive yourself; ask someone to take you [1].
Why Does Glucophage Upset the Stomach, and How Can I Ease It?
Digestive side effects are the most common. They include nausea or vomiting, diarrhoea, abdominal pain, loss of appetite and taste changes [1]. Gas, indigestion and constipation may also occur [2]. Most of these symptoms ease after about two weeks as the body adjusts, although some may last longer [1].
Steps to Reduce Discomfort
- Take the medicine with a meal or right after eating, not on an empty stomach.
- Follow the dose increases your doctor has set [2].
- Ask your doctor or pharmacist about the extended-release (XR) form, which eases symptoms for many people.
- Tell your pharmacist or doctor if symptoms bother you or do not go away. They may offer advice that reduces side effects, so do not stop the medicine unless you are asked to [1].
Watch for vomiting, diarrhoea or fever during treatment, as these can lead to dehydration. In that case, contact your pharmacist or doctor to find out whether you need to pause the medicine temporarily [1] [2]. If you have diabetes and experience early fullness and repeated vomiting, the cause may be different from the medicine, as in gastroparesis in people with diabetes, and it needs evaluation by a doctor. (Note: see link below.)
Does Glucophage Cause Vitamin B12 Deficiency?
Yes, this can happen. The NHS lists vitamin B12 deficiency among the common effects of metformin, and it can make a person feel extremely tired [1]. It usually occurs with long-term use, so levels are checked regularly as the doctor judges appropriate. It is advisable to tell your doctor if your vitamin B12 level has been low in the past [2].
The body needs this vitamin for the nerves and for making blood. Along with tiredness, some patients may report numbness or pallor. These are general symptoms that the doctor assesses through examination. To learn about the condition, read the vitamin B12 deficiency page.
- Ask for a B12 test as part of regular follow-up, especially with long-term use or unexplained tiredness.
- Do not start B12 supplements or injections on your own. Your doctor decides whether you need them and at what dose, based on the test result.
- If you follow a plant-based diet, read Why do vegans need B12? (Note: no English page available.)
When Might a Doctor Stop Glucophage Temporarily? Imaging, Surgery, Dehydration and Kidneys
In some situations, your doctor may ask you to stop the medicine for a short period and then restart it. The decision always rests with your doctor or the imaging department, not with you.
| Situation | What Usually Happens |
|---|---|
| Imaging with an intravenous contrast dye | It may need to be stopped before the procedure and not restarted for at least 48 hours; your doctor will specify the exact timing [2] |
| Surgery, including dental surgery, or a major medical procedure | Tell your doctor you take it, as they may pause it temporarily [2] |
| Severe infection, or severe diarrhoea, vomiting or fever, or drinking much less fluid than usual | It may need to be stopped until you recover, so contact your doctor [2] |
| Kidney problems | The doctor orders tests before and during treatment to check kidney function [2], and it may not suit some patients [1] |
Tell every doctor, radiology technician or dentist that you take metformin, and carry a written list of your medicines and supplements to every visit [2]. Kidney assessment usually relies on a kidney function test (eGFR), and your doctor will determine the appropriate threshold for you. It may also help to read about the HbA1c test to understand long-term diabetes monitoring.
Is Glucophage Safe? Rare Lactic Acidosis and Who It May Not Suit
Metformin is safe for most patients when used under medical supervision. However, it carries an important warning: lactic acidosis, meaning an increase in the acidity of the blood. It is rare but can be life-threatening [2]. The risk increases with kidney disease, age over 65, and a history of heart attack, stroke, or heart or liver disease [2].
Who May Not Be Suited to the Medicine?
- People with liver or kidney problems, heart failure, or severe infection [1].
- People who drink large amounts of alcohol [1].
- People who have previously had an allergic reaction or a serious side effect from metformin [1]. See drug allergy.
Drug Interactions and Alcohol
Alcohol increases the risk of lactic acidosis and may lower blood sugar, so ask your doctor about a safe amount, if any [2]. Metformin may also interact with diuretics, NSAID painkillers such as ibuprofen and diclofenac, and some blood pressure medicines [1]. The source also highlights medicines such as acetazolamide, topiramate and zonisamide [2]. Tell your doctor and pharmacist about all medicines, herbs and supplements you take [1].
Metformin alone does not usually cause low blood sugar, but the risk increases when it is combined with other medicines such as insulin [1]. It is advisable to know the symptoms of low and high blood sugar and what to do if they occur [2] [3]. In Jordan, medicines and their general prices are regulated by the Jordan Food and Drug Administration (JFDA), so buy your medicine from a licensed pharmacy and ask the pharmacist about any questions.
Is Glucophage Used for PCOS and Pregnancy?
Doctors sometimes prescribe it for polycystic ovary syndrome (PCOS) to help improve ovulation and regulate hormones. The NHS states that it is used for the symptoms of this syndrome [1]. The decision and dose rest with the doctor after assessment. It should not be started for this purpose, or for weight loss, without a prescription, as it is available only on prescription [1].
Regarding pregnancy, the NHS says it can be taken during pregnancy after consulting a doctor, and that uncontrolled diabetes may increase the risk of complications, including miscarriage [1]. Therefore, tell your doctor as soon as you find out you are pregnant, and do not stop the medicine on your own. Review Should I stop taking metformin when I find out I am pregnant? Insulin may sometimes be needed during pregnancy [3].
As for breastfeeding, the medicine passes into breast milk in small amounts and can usually be taken, but only after consulting a doctor [1].
When Should I See a Doctor, and When Should I Go to the Emergency Room?
Go to the Emergency Room or Call 911 Immediately If You Have:
- Severe tiredness or weakness, together with nausea, vomiting and abdominal pain [2].
- Deep, rapid breathing or shortness of breath, or muscle cramps [1] [2].
- Dizziness, rapid or slow heartbeat, or cold hands and feet [2].
- Swelling of the throat or tongue, a raised itchy rash, or difficulty breathing, which are signs of a severe allergic reaction [1].
- Chest pain [2], or collapse, seizures, or difficulty waking up after an overdose [2].
Tell the medical team that you take metformin. Sources advise stopping it and contacting a doctor immediately if symptoms of lactic acidosis appear [2], so get urgent medical care without delay.
See Your Doctor Soon If You Have:
- Nausea or bothersome diarrhoea that does not go away after weeks, or that returns after having resolved [1] [2].
- Yellowing of the skin or whites of the eyes, which may indicate liver inflammation [1]. Yellowing may be less obvious on darker skin.
- Persistent unexplained tiredness, which may be linked to vitamin B12 deficiency [1].
- Vomiting, diarrhoea or fever that has caused dehydration [1].
How Do I Find the Right Doctor for Diabetes Follow-Up in Jordan?
Following up on Glucophage treatment requires a doctor who reviews your dose and tests regularly. You can search the directory of endocrinology and diabetes doctors in Jordan, or filter by governorate, such as Amman, Irbid or Zarqa. Pages for other governorates are available from the specialty page. There are also Ministry of Health primary health centres in the governorates that are useful for initial follow-up.
What to Check in a Doctor's Profile
- The specialty (endocrinology and diabetes or internal medicine), the clinic location and working hours.
- How to contact or book an appointment, as provided in the profile.
- The services offered, such as diabetes consultation and diabetes testing.
Questions to Ask at Your Appointment
- Is the regular or extended-release (XR) form more suitable for my stomach?
- When should I have kidney function and vitamin B12 tests?
- What should I do if I have diarrhoea or vomiting, and should I pause the medicine temporarily?
- Do my other medicines interact with metformin?
- What are my instructions before any contrast imaging or surgery?
Bring a list of your medicines and your previous test results. Remember that the goal of following up on Glucophage treatment is to keep blood sugar controlled with as few side effects as possible, and safely.
This article is for general health education and does not replace consulting your doctor or pharmacist about your condition.
Frequently asked questions
What is Glucophage and why do doctors prescribe it?
Glucophage is the brand name for metformin, which belongs to the biguanide class. It is used to treat type 2 diabetes, alone or with other medicines, including insulin. It helps control blood sugar by reducing how much glucose the body absorbs from food and how much the liver produces, and by improving the body's response to insulin. The medicine alone is not enough, and healthy eating and physical activity remain part of the plan. It controls diabetes but does not cure it.
How is Glucophage taken?
It is recommended to take it with food, and most people take it once to three times a day. The usual dose is set by your doctor or pharmacist, and you should not increase or decrease it on your own. Doctors often start with a low dose and raise it gradually to reduce stomach upset. Always follow what is written on your box and leaflet, and continue taking the medicine even if you feel better.
What should I do if I miss a dose or take too much?
If you take it once a day and forget a dose, take it as soon as you remember, unless the next dose is almost due. Never double a dose to make up for a missed one. If you have taken more than prescribed, call the emergency services or go to the nearest emergency department, and bring the medicine box, the leaflet and any other medicines you are taking. Do not drive yourself; ask someone to take you.
What are the most common side effects of Glucophage and how can I ease them?
The most common side effects are digestive, including nausea or vomiting, diarrhoea and abdominal pain. Most of these symptoms ease after about two weeks as the body adjusts. To ease them, take the medicine with a meal or right after eating, follow the gradual dose increases set by your doctor, and ask your doctor or pharmacist about the extended-release (XR) form, which eases symptoms for many people. Do not stop the medicine on your own.
Does Glucophage cause vitamin B12 deficiency?
Yes, this can happen. The NHS lists vitamin B12 deficiency among the common effects of metformin. It usually occurs with long-term use, so levels are checked regularly as the doctor judges appropriate. The body needs this vitamin for the nerves and for making blood, and it can make a person feel extremely tired. Ask for a B12 test as part of follow-up, and do not start B12 supplements or injections on your own, as your doctor decides whether you need them and at what dose.
Is Glucophage safe for most patients?
It is safe for most patients when used under medical supervision. However, it carries an important warning, lactic acidosis, which is rare but can be life-threatening. The risk increases with kidney disease, age over 65, and a history of heart attack or stroke. It is not suited to people with liver or kidney problems, heart failure, or those who drink large amounts of alcohol. Tell your doctor about all medicines you take.
Sources and references
- Metformin: a medicine to treat type 2 diabetes — NHS (UK National Health Service). Accessed: 2026-10-26.
- Metformin: MedlinePlus Drug Information — MedlinePlus — U.S. National Library of Medicine. Accessed: 2026-10-26.
- Diabetes Medicine | Insulin — MedlinePlus — U.S. National Library of Medicine. Accessed: 2026-10-26.
