Metformin (Oral)

Metformin is used alone or with other medications in the treatment of type II diabetes mellitus.


Metformin is used to treat patients who are suffering from a form of diabetes mellitus known as type II diabetes. Type II diabetes is known as sugar diabetes and results in there being high levels of sugar in the blood. With type II diabetes the insulin produced by the pancreas cannot absorb the sugar in the blood and transfer it into the cells to be utilized, leading to greater levels of sugar being present in the blood.

If left uncontrolled type II diabetes can have very serious consequences. Type II diabetes can lead to vision loss, blindness, kidney failure, heart attack and stroke. If you have been diagnosed with this condition then it is essential that you take steps to control it or these complications will occur.

Metformin, when used alone, with sulfonylura or with insulin, can help to lower the blood sugar levels when it is too high. It can also help in making the process of turning food into energy more efficient to help with the consumption of the sugar in the blood.

Patients with type II diabetes can control their condition through diet and exercise and this will always be prescribed alongside Metformin. Your doctor will give you a special diet and exercise plan that you will need to follow when you have diabetes. Control of the condition must also come from your food intake and exercise as well as from treatments such as Metformin. To work properly you must take a dose that is balanced against your diet and exercise, so changes in your routine will affect the treatment.

Patients taking Metformin will need to test their blood sugar to determine their levels and know if the levels are too low. The doctor will be able to help you to understand how to manage the levels of sugar in your blood.

Metformin is not in any way helpful to patients who are suffering from type I diabetes as they do not produce any insulin. These patients will instead need to be treated with insulin injections.

Metformin is available only with a doctor's prescription and will be administered as a tablet, extended release tablet or solution. The medication is available in the following brands:

  • Riomet
  • Glumetza
  • Glucophage XR
  • Glucophage
  • Fortamet

Condition treated

  • Type II diabetes
  • High blood sugar

Type Of Medicine

  • Biguanides

Side Effects

In addition to lowering the level of sugar in the blood, Metformin can also have a range of other side effects. These unwanted side effects may not all occur but when they do the patient may need to seek medical attention.

Patients should seek immediate medical attention if they are experiencing any of the following side effects:
Occurring more commonly:

  • Sleepiness
  • Painful or difficult urination
  • Muscle pain or cramping
  • Lower back or side pain
  • General feeling of discomfort
  • Fever or chills
  • Fast or shallow breathing
  • Diarrhea
  • Decreased appetite
  • Cough or hoarseness
  • Abdominal or stomach discomfort

Occurring less commonly:

  • Wheezing
  • Unusual tiredness or weakness
  • Tightness in the chest
  • Slurred speech
  • Shortness of breath
  • Shakiness
  • Seizures
  • Redness of the face, neck, arms, and occasionally, upper chest
  • Nightmares
  • Nervousness
  • Nausea
  • Increased sweating
  • Increased hunger
  • Headache
  • Feeling of warmth
  • Fast, irregular, pounding, or racing heartbeat or pulse
  • Dizziness
  • Difficult or labored breathing
  • Depression
  • Cool, pale skin
  • Confusion
  • Coma
  • Cold sweats
  • Chest discomfort
  • Blurred vision
  • Anxiety

Occurring only rarely:

  • Unusual sleepiness
  • Restless sleep
  • Lack or loss of strength
  • Drowsiness
  • Difficulty with concentrating
  • Behavior change similar to being drunk

Certain other side effects can also occur that do not normally require that the patient seeks medical attention. These side effects are milder, usually abate over time as the body gets used to the treatment and do not normally indicate any other wider medical complications that may be occurring. If these side effects are to become bothering or are ongoing, however, then you should seek advice from your healthcare professional:
Occurring more commonly:

  • Weight loss
  • Vomiting
  • Stomachache
  • Stomach upset or pain
  • Passing of gas
  • Metallic taste in the mouth
  • Loss of appetite
  • Indigestion
  • Heartburn
  • Full feeling
  • Excess air or gas in the stomach or intestines
  • Bloated
  • Belching
  • Acid or sour stomach

Occurring less commonly:

  • Swollen joints
  • Stuffy nose
  • Sneezing
  • Runny nose
  • Rash
  • Joint pain
  • Flu-like symptoms
  • Discoloration of the fingernails or toenails
  • Difficulty with moving
  • Change in taste
  • Bad, unusual, or unpleasant (after) taste
  • Abnormal stools

Metformin could also cause other side effects that have not been listed herein to occur. If you experience any other side effects then you should contact your doctor for advice. If you believe your health to be at immediate risk, however, then you should seek emergency assistance.


This medication will be provided with a patient information guide. You should ensure that you have read and fully understand the guide. If you do not understand anything then consult your doctor for advice.

The dietary and exercise plans that your doctor gives you with this medication are essential parts of controlling your condition. These controls are necessary in preventing the condition from developing and serious medical complications from occurring. You must eat properly, exercise regularly and test your blood or urine for sugar as you have been directed to by your doctor.

Metformin can be taken with food and this will help to reduce the stomach and bowel discomfort that can occur. This is especially important in the first few weeks of treatment when this discomfort is more common and more severe.

The extended release tablets must be swallowed whole and should not be broken in any way. Do not take a broken tablet.

The oral liquid version of this medication should be measured using only the provided device. Do not use other utensils as these may be inaccurate for the required dose.

You must only use the prescribed brand of this medication and should never swap brands. The different brands work in different ways and will have different effects and side effects.

Initial effects may be noticed after 1-2 weeks of use. The full effects of control will take 2-3 months to be realized, however. You should ask your doctor if you have any questions about this but should keep taking the medication as directed at all times.

The dose of this medication that you are given will depend on a wide range of factors and is entirely personal to you. The effects and strengths of the treatments across brands are different so you should not ever take a different brand of the treatment. Follow your doctor's directions at all times. The following information is for the purpose of being a guideline only and should not be used to adjust your dose:

For the treatment of adults:
When using the Metformin extended release tablets without other treatment:

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    • Fortamet'nitially the patient should be treated with 1000mg taken once daily with the evening meal. This may be increased until the blood sugar is controlled but should not exceed 2500mg per day.
    • Glucophage' Initially 500mg should be taken once daily with the evening meal. This dose may be increased to a maximum of 2000mg until the blood sugar is controlled.
    • Glumetza' Initially the patient can be treated with 500mg taken once daily with an evening meal. The dose can be upped to a maximum of 2000mg until the blood sugar is under control.

When using the Metformin extended release tablets with sulfonylurea:

    • The doctor will determine usage in each case.

When using the Metformin extended release tablets with insulin:

    • Initially the patient should be given 500mg per day. This should be increased by 500mg each week until the blood sugar is controlled. The dose should not exceed 2500mg, however.

When using the Metformin tablets without other treatment:

    • Initially the patients should receive 500mg of medication twice daily. This dose may be increased to 500-850mg taken 3 times daily. The dose should be taken with meals and should not exceed 2500mg in a day.

When using the Metformin tablets with sulfonylurea:

    • The doctor will determine the dose to be taken in each individual case.

When using the Metformin tablets with insulin:

  • The patient should be treated with 500mg per day at first. This may be increased by 500mg per week up to a maximum of 2500mg. Increase the dose until the blood sugar is controlled.

For the treatment of children:
When using the Metformin tablets with insulin:

  • Children between the ages of 10-16 should initially be treated with 500mg taken twice daily with breakfast and dinner. The dose may be increased to a maximum of 2000mg taken each day.
  • Children below the age of 10 will need to have their dose calculated in each case by the doctor.

If you miss a dose of this medication that has been prescribed then you should take it as soon as possible with a small healthy snack. If you are close to your next dose being due, however, then you should skip the dose you have missed and return to your normal schedule of dosing. Do not ever take a double dose of this medication.


Certain medications should ever be used together. This is because they can interact with one another in the body and cause severe medical problems to occur. In other cases medications may prevent one another from working or increase the side effects that are suffered from use. To avoid interactions you must inform your doctor of all medications that you are taking and must not take any other medications that have not been approved for use by your doctor. This includes all over the counter medications, prescribed medications, supplements and herbal remedies. For the use of Metformin it is especially important that you inform your doctor if you are taking any of the following:

The use of Metformin is not recommended with any of the following treatments. Your doctor may decide not to use this treatment at all if you are taking any of these:

  • Tyropanoate Sodium
  • Metrizoic Acid
  • Metrizamide
  • Ipodate
  • Ioxitalamic Acid
  • Ioxaglate
  • Ioversol
  • Iotroxic Acid
  • Iotrolan
  • Iothalamate
  • Iotasul
  • Iosimide
  • Ioseric Acid
  • Iopronic Acid
  • Iopromide
  • Iophendylate
  • Iopentol
  • Iopanoic Acid
  • Iopamidol
  • Iomeprol
  • Iohexol
  • Ioglycamic Acid
  • Ioglicic Acid
  • Iodoxamic Acid
  • Iodopyracet
  • Iodohippuric Acid
  • Iodixanol
  • Iodipamide
  • Iodamide
  • Iocetamic Acid
  • Iocarmic Acid
  • Iobitridol
  • Iobenzamic Acid
  • Ethiodized Oil
  • Diatrizoate
  • Acetrizoic Acid

The use of these medications with Metformin is not normally recommended but in some cases may be required. Where this is the case the doctor may prescribe both but may change the dose or frequency of use of one or other medication:

  • Vandetanib
  • Tosufloxacin
  • Thioctic Acid
  • Sparfloxacin
  • Rufloxacin
  • Ritonavir
  • Prulifloxacin
  • Pefloxacin
  • Pazufloxacin
  • Pasireotide
  • Paritaprevir
  • Ombitasvir
  • Ofloxacin
  • Octreotide
  • Norfloxacin
  • Nadifloxacin
  • Moxifloxacin
  • Lomefloxacin
  • Levofloxacin
  • Lanreotide
  • Gemifloxacin
  • Gatifloxacin
  • Flumequine
  • Fleroxacin
  • Enoxacin
  • Dolutegravir
  • Dofetilide
  • Dasabuvir
  • Ciprofloxacin
  • Bupropion
  • Besifloxacin
  • Balofloxacin
  • Aspirin

Using the following medications with Metformin can increase the risk of side effects occurring. In some cases the use of both may still be required, however, and the doctor may make changes to the frequency of use and dose before prescribing both:

  • Tranylcypromine
  • Timolol
  • Sotalol
  • Selegiline
  • Safinamide
  • Rifampin
  • Rasagiline
  • Ranolazine
  • Psyllium
  • Propranolol
  • Procarbazine
  • Practolol
  • Pindolol
  • Phenelzine
  • Penbutolol
  • Patiromer
  • Oxprenolol
  • Nialamide
  • Nebivolol
  • Nadolol
  • Moclobemide
  • Metoprolol
  • Metipranolol
  • Methylene Blue
  • Linezolid
  • Levobunolol
  • Labetalol
  • Isocarboxazid
  • Iproniazid
  • Guar Gum
  • Glucomannan
  • Furazolidone
  • Fenugreek
  • Esmolol
  • Celiprolol
  • Carvedilol
  • Carteolol
  • Bitter Melon
  • Bisoprolol
  • Betaxolol
  • Atenolol
  • Acebutolol

Other medications that have not been listed herein could also interact with Metformin in the body. You must ensure that your doctor knows of all substances you take before you begin treatment and should check with your doctor before taking any medication once you have begun treatment.

The foods and drinks that you consume when taking Metformin will also interact with the medication. This medication can only effectively control blood sugar levels when you are following a balanced diet and exercising regularly. Changes in your diet or cessation of exercise will make the treatment ineffectual and can lead to the development of further problems.

The presence of other medical problems can also affect the use of this medication. You must inform your doctor if you have any other medial conditions before use and this is especially important in the following cases:
These conditions will increase the likelihood of suffering low blood sugar levels:

  • Excessive alcohol use
  • Underactive adrenal glands
  • Underactive pituitary glands
  • Undernourishment
  • Weakened physical condition

These conditions may be worsened by the use of Metformin:

  • Anemia
  • Vitamin B12 deficiency

Patients with these conditions may develop lactic acidosis:

Patients with these conditions should not be treated with Metformin:

  • Diabetic ketoacidosis
  • Severe kidney disease
  • Metabolic acidosis
  • Type I diabetes

Patients who develop these conditions during use of Metformin may need further treatment to control blood sugar levels:

  • Fever
  • Infection
  • Surgery
  • Trauma

Other medical problems could also affect the use of Metformin that have not been listed. Ensure your doctor has access to your full medical history before you begin use of this treatment.


Before you begin using Metformin it is essential that you understand the risks of use and the risks of incorrect use. You should weigh these risks against the benefits of treatment in making your decision to take Metformin. You should decide to use Metformin with your doctor having ensured that you have taken the following into account:

Allergies' You must inform your doctor of all allergies that you have suffered from in the past. If you have ever reacted badly to a medicine of this type then you may be prohibited from use. You should also inform your doctor of all allergies that you have to foods, dyes, preservatives, animals and other substances.

PediatricĀ ' The use of this medication has been tested for safety and efficiency in some forms for children between the ages of 10-16. Consult your doctor about child use before beginning treatment and follow prescriptions exactly at all times.


Pregnancy' There is a minimal risk to the use of this medication when pregnant. There are, however, serious risks to pregnancy when you are suffering from type II diabetes. You should discuss these risks with your doctor and may be offered counseling.

Breastfeeding' There is a minimal risk to the use of this medication when breastfeeding. Discuss this with your doctor before beginning use.

You and your doctor will need to regularly check your blood sugar levels when taking this medication. You will need to make regular visits to your doctor in the first few weeks of use and then into the future too. These tests will look for unwanted effects and will also ensure that the medication is working properly and the dosing is correct.

This medication can interact with certain dyes that are used in CT and X-Ray scans. You must inform your doctor that you are taking this treatment before you undergo any tests, surgeries and procedures. Your doctor will tell you to stop taking this medication in advance of certain treatments and it is advised that you wait for at least 48 hours after treatments to begin taking it again. Your kidneys may be tested for function before you are allowed to start again.

Any doctor or dentist must be informed that you are taking this treatment.

When you begin this treatment you will need to make changes to your lifestyle in order to control your health. You will be given a lot of advice and it is important that you follow all of the advice given to you, especially on the following topics:

  • Alcohol'Alcohol consumption will need to be stopped when you start this treatment. Consuming alcohol and particularly consuming a lot of alcohol will cause your blood sugar to drop dramatically and can cause complications. A rare condition called lactic acidosis is also more likely to occur if you drink during use of Metformin. You should discuss this with your doctor.
  • Other medications ' You should never take any other medication with Metformin unless it has been approved by the doctor for use in advance. Over the counter treatments for mild and common conditions can interact with Metformin can may cause serious medical complications to occur.
  • Counseling 'You and other family members may need counseling to help deal with the side effects and the lifestyle changes that will be required to deal with your condition. They may also need to make lifestyle changes in order that they may avoid becoming unwell with the same condition as you. Counseling will also touch on birth control.
  • Pregnancy' There are severe risks to pregnancy when you are suffering from diabetes type II and you will be informed of the need to use birth control to prevent pregnancy from occurring. You may be offered counseling to help come to terms with this, but pregnancy is not advised with this condition.
  • Traveling' When traveling you will need to take extra precautions to control your condition. This includes ensuring that you have access to your treatment and taking time zone changes into account in your dosing schedule.
  • Emergency careĀ ' With this condition it is highly likely that you will need to receive emergency care at some point in your life. This can occur because of a drop in blood sugar or for any other reason. You will be taught how to prevent this by noticing warning signs and will also be advised to wear an identification bracelet at all times. You should also carry an ID card with details of your medication in your wallet or purse for safety. This will help the emergency services to give you the correct treatment and will increase your chance of survival.

In some cases a rare condition known as lactic acidosis may occur from taking Metformin. The symptoms of this condition are severe and need to be treated immediately. The condition is more likely to occur where other medical conditions are also present or when an excessive amount of alcohol is consumed. You should call for emergency help if you experience these symptoms:

  • Stomach pain
  • Abdominal discomfort
  • Decreased appetite
  • Diarrhea
  • Shallow breathing
  • Discomfort
  • Muscle pains or cramps
  • Unusual tiredness
  • Unusual weakness

Metformin can cause low blood sugar levels to occur. This can also occur if you miss meals or over exercise, however. The control of your blood sugar needs to be consistent and regular in order for the blood sugar to be maintained. If you get hypoglycaemia (low blood sugar) you will experience the following symptoms:

    • Anxiety
    • Feeling of drunkenness
    • Excessive hunger
    • Increased heartbeat
    • Nightmares
    • Restlessness
    • Shakiness
    • Slurring of speech
    • Unusual weakness
    • Unusual tiredness
    • Nausea
    • Headache

You will need to learn to notice these symptoms and know how to react before consciousness is lost. If you experience these symptoms you will need to increase your blood sugar level by eating sugary foods with a high concentration. In emergency situation glucagon is used to prevent seizures and unconsciousness. You should always have a kit for this treatment with you and should teach those who spend time with you how and when to use it.

If you do not exercise to the normal level and regularly then your blood sugar level may increase again. This may also occur if you have a fever of if you miss a dose of medication. It will also occur if you overeat or eat the wrong sort of foods. If you have a high blood sugar level then you should test the level and contact your doctor for advice.

Metformin alone is not an effective treatment. It needs to form a part of a wider lifestyle and diet that will help to control your blood sugar level. At the point of diagnosis you have an opportunity to change and prolong your life with treatment with Metformin and you should take this opportunity to lose weight, get healthy and control your condition so it does not impact your life and lead to blindness, heart attack, stroke or kidney failure.


You should store this medication in a sealed container at room temperature.

Keep the medication away from heat, direct light, moisture and freezing temperatures.

Keep this medication out of the reach of children even when it is intended for their use.

Dispose of any unwanted medication promptly as directed by your prescribing doctor.


Metformin is a treatment that is used to help in the control of blood sugar levels in patients who are suffering from diabetes type II. This is a condition wherein the body is unable to deal with sugar properly and it builds up in the blood.

If diabetes type II is not controlled then you will suffer medical complications that can be life-threatening and life-changing. Complications that will occur include blindness during working-age, heart attack, kidney failure and stroke.

Metformin can help in the prevention of these complications by helping to control blood sugar levels, but the patient will be responsible for the effectiveness of the treatment. Patients can effectively control blood sugar levels through exercise, diet and the use of Metformin, but all three aspects need to be steady, regular and consistent in order for it to work. Overeating will increase blood sugar levels as will skipping a dose or missing exercise so this treatment needs to be a collective drive towards healthier living.

Patients should not take any other kind of medication with this treatment unless it has been approved by the prescribing doctor. To do so can cause medication interactions to occur that can be very dangerous to the patient.

Patients being treated with Metformin need to avoid the use of central nervous system depressants including alcohol and common over the counter medications. Use of these substances will be intensified and the side effects can be severe when using Metformin.