Metformin Tablets 500mg and 850mg Package leaflet: Information for the user – patient leaflet, side effects, dosage

1. What Metformin Tablets are and what they are used for

Metformin Tablets contain the active substance metformin hydrochloride. Metformin belongs to a group of medicines called biguanides.

Insulin is a hormone produced by the pancreas that makes your body take in glucose (sugar) from the blood. Your body uses glucose to produce energy or stores it for future use.

If you have diabetes, your pancreas does not make enough insulin or your body is not able to use properly the insulin it produces. This leads to a high level of glucose in your blood. Metformin helps to lower your blood glucose to as normal a level as possible.

If you are an overweight adult, taking Metformin over a long period of time also helps to lower the risk of complications associated with diabetes. Metformin is associated with either a stable body weight or modest weight loss.

Metformin is used to treat patients with type 2 diabetes (also called 'non-insulin dependent diabetes') when diet and exercise alone have not been enough to control your blood glucose levels. It is used particularly in overweight patients.

Adults can take Metformin on its own or together with other medicines to treat diabetes (medicines taken by mouth or insulin).

Children 10 years and over and adolescents can take Metformin on its own or together with insulin.

2. What you need to know before you take Metformin Tablets

Do not take Metformin Tablets if you:

• are allergic to metformin hydrochloride or any of the other

  ingredients of this medicine (listed in section 6). · have liver problems

• have severely reduced kidney function.

• have uncontrolled diabetes, with, for example, severe

  hyperglycaemia (high blood glucose), nausea, vomiting, diarrhoea, rapid weight loss, lactic acidosis (see section “Risk of lactic acidosis” below) or ketoacidosis. Ketoacidosis is a condition in which substances called 'ketone bodies' accumulate in the blood and which can lead to diabetic pre-coma. Symptoms include stomach pain, fast and deep breathing, sleepiness or your breath developing an unusual fruity smell.

• lost too much water from your body (dehydration), such

  as due to long-lasting or severe diarrhoea, or if you have vomited several times in a row. Dehydration may lead to kidney problems, which can put you at risk for lactic acidosis (see 'Warnings and precautions'). · have a severe infection, such as an infection affecting

  your lung or bronchial system or your kidney. Severe infections may lead to kidney problems, which can put you at risk for lactic acidosis (see ' Warnings and precautions').

• are treated for acute heart failure or have recently had a

  heart attack, have severe problems with your circulation (such as shock) or have breathing difficulties. This may lead to a lack in oxygen supply to tissue which can put you at risk for lactic acidosis (see ' Warnings and precautions')

• drink a lot of alcohol

If any of the above applies to you, talk to your doctor, before you start taking this medicine.

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Pregnancy and breast-feeding

If you are pregnant, think you may be pregnant or are planning to have a baby, speak to your doctor in case any changes will be needed to your treatment or monitoring of your blood glucose levels.

This medicine is not recommended if you are breast-feeding or if you are planning to breast-feed your baby.

Driving and using machines

Metformin on its own does not cause hypoglycaemia (a blood glucose level which is too low). This means that it will not affect your ability to drive or use machines.

However, take special care if you take Metformin together with other medicines to treat diabetes that can cause hypoglycaemia (such as sulphonylureas, insulin, meglitinides). Symptoms of hypoglycaemia include weakness, dizziness, increased sweating, fast heartbeat, vision disorders or difficulty in concentration. Do not drive or use machines if you start to feel these symptoms.

Sodium content

Metformin 500mg Tablets - This medicine contains 4.7 mg sodium (main component of cooking/table salt) in each tablet. This is equivalent to 0.24% of the recommended maximum daily dietary intake of sodium for an adult.

Metformin 850mg Tablets - This medicine contains 8 mg sodium (main component of cooking/table salt) in each tablet. This is equivalent to 0.4% of the recommended maximum daily dietary intake of sodium for an adult.

Propylene glycol content

Metformin 500mg Tablets - This medicine contains 0.323 mg propylene glycol in each tablet which is equivalent to 1.938 mg/dose.

Metformin 850mg Tablets - This medicine contains 0.526 mg propylene glycol in each tablet which is equivalent to 1.841 mg/dose.

3. How to take Metformin Tablets

Always take this medicine exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.

Metformin cannot replace the benefits of a healthy lifestyle. Continue to follow any advice about diet that your doctor has given you and get some regular exercise.

Recommended dose

Children 10 years and over and adolescents usually start with 500 mg or 850 mg Metformin once a day. The maximum daily dose is 2000 mg taken as 2 or 3 divided doses. Treatment of children between 10 and 12 years of age is only recommended on specific advice from your doctor, as experience in this age group is limited.

Adults usually start with 500 mg or 850 mg Metformin two or three times a day. The maximum daily dose is 3000 mg taken as 3 divided doses. If you have reduced kidney function, your doctor may prescribe a lower dose.

If you take insulin too, your doctor will tell you how to start Metformin.

Monitoring

• Your doctor will perform regular blood glucose tests and

  will adapt your dose of Metformin to your blood glucose levels. Make sure that you talk to your doctor regularly. This is particularly important for children and adolescent or if you are an older person.

• Your doctor will also check at least once a year how well

  your kidneys work. You may need more frequent checks if you are an older person or if your kidneys are not working normally.

How to take Metformin Tablets

Take Metformin with or after a meal. This will avoid you having side effects affecting your digestion.

Do not crush or chew the tablets. Swallow each tablet with a glass of water.

• If you take one dose a day, take it in the morning

  (breakfast)

• If you take two divided doses a day, take them in the

  morning (breakfast) and evening (dinner)

• If you take three divided doses a day, take them in the

  morning (breakfast), at noon (lunch) and in the evening (dinner)

If, after some time, you think that the effect of Metformin is too strong or too weak, talk to your doctor or pharmacist.

If you take more Metformin Tablets than you should

If you have taken more Metformin than you should have, you may experience lactic acidosis. Symptoms of lactic acidosis are non-specific such as vomiting, bellyache (abdominal pain) with muscle cramps, a general feeling of not being well with severe tiredness, and difficulty in breathing. Further symptoms are reduced body temperature and heartbeat. If you experience some of these symptoms, you should seek immediately medical attention, as lactic acidosis may lead to coma. Stop taking Metformin tablets immediately and contact a doctor or the nearest hospital straight away.

If you forget to take Metformin Tablets

Do not take a double dose to make up for a forgotten dose. Take the next dose at the usual time.

If you have any further questions on the use of this medicine ask your doctor or pharmacist. ^ENV02

If you stop taking Metformin tablets

You should finish all the tablets your doctor has prescribed. Do not stop taking your medicine, even if you feel better, as it may be dangerous to stop taking the medicine without your doctor's advice.

If you have any further questions on the use of this medicine, ask your doctor or pharmacist.

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.

The following side effects may occur:

Metformin may cause a very rare (may affect up to 1 user in 10,000), but very serious side effect called lactic acidosis (see section 'Warnings and precautions'). If this happens you must stop taking Metformin and contact a doctor or the nearest hospital immediately, as lactic acidosis may lead to coma.

Very common side effects (in more than 1 in 10 people)

• digestive problems, such as feeling sick (nausea), being sick (vomiting), diarrhoea, bellyache (abdominal pain) and loss of appetite. These side effects most often happen at the beginning of the treatment with Metformin. It helps if you spread the doses over the day and if you take the Metformin with or straight after a meal. If symptoms continue, stop taking Metformin tablets and talk to your doctor.

Common side effects (in less than 1 in 10 people)

• changes in taste

• decreased or low vitamin B12 levels in the blood

  (symptoms may include extreme tiredness (fatigue), a sore and red tongue (glossitis), pins and needles (paraesthesia) or pale or yellow skin). Your doctor may arrange some tests to find out the cause of your symptoms because some of these may also be caused by diabetes or due to other unrelated health problems.

Very rare side effects (in less than 1 in 10,000 people)

• lactic acidosis. This is very rare but serious complication particularly if your kidneys are not working properly. Symptoms of lactic acidosis are non-specific (see section 'Warning and precautions')

• abnormalities in liver function tests or hepatitis

  (inflammation of the liver; this may cause tiredness, loss of appetite, weight loss, with or without yellowing of the skin or whites of the eyes). If this happens to you, stop taking Metformin tablets and talk to your doctor.

• skin reactions such as redness of the skin (erythema), itching or an itchy rash (hives).

Children and adolescents

Limited data in children and adolescents showed that adverse events were similar in nature and severity to those reported in adults.

Reporting of side effects

If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.

5. How to store Metformin tablets

Keep this medicine out of the sight and reach of children.

Do not use this medicine after the expiry date which is stated on the carton. The expiry date refers to the last day of that month.

Store below 25°C in a dry place.

Do not use this medicine if you notice any defects in the tablets, such as broken or chipped tablets, take them to your pharmacist for advice.

Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.

6. Contents of the pack and other information

What Metformin tablets contain

The active substance is metformin hydrochloride. Each film-coated tablet contains 500mg or 850mg of metformin hydrochloride.

The other ingredients are sodium starch glycollate, maize starch, povidone, colloidal anhydrous silica, magnesium stearate, methylhydroxypropylcellulose, propylene glycol, polyethylene glycol, purified talc, and titanium dioxide (E171).

What Metformin tablets look like and contents of the pack

Metformin Tablets are supplied in packs of 28, 30, 56, 60, 84, 90, 100 or 112 tablets. However, the quantity dispensed by the pharmacist will be according to your prescription. Not all pack sizes may be marketed.

Marketing Authorisation Holder

Ennogen IP Ltd

Unit G4, Riverside Industrial Estate, Riverside Way, Dartford, DA1 5BS, UK.

Manufacturer

Sandoz Limited, 200 Frimley Business Park, Frimley, Camberley, GU16 7SR, UK

This leaflet was last revised in March 2025.

Make sure you ask your doctor for advice, if:

• you need to have an examination such as X-ray or scan

  involving the injection of contrast medicines that contain iodine into your bloodstream

• you need to have major surgery

You must stop taking Metformin for a certain period of time before and after the examination or the surgery. Your doctor will decide whether you need any other treatment for this time. It is important that you follow your doctor's instructions precisely.

Warnings and precautions

Risk of lactic acidosis.

Metformin may cause a very rare, but very serious side effect called lactic acidosis, particularly if your kidneys are not working properly. The risk of developing lactic acidosis is also increased with uncontrolled diabetes, serious infections, prolonged fasting or alcohol intake, dehydration (see further information below), liver problems and any medical conditions in which a part of the body has a reduced supply of oxygen (such as acute severe heart disease). If any of the above apply to you, talk to your doctor for further instructions.

Talk to your doctor promptly for further instructions if:

! you are known to suffer from a genetically inherited

disease affecting mitochondria (the energy-producing components within cells) such as MELAS syndrome (Mitochondrial Encephalopathy, myopathy, Lactic acidosis and Stroke-like episodes) or Maternal inherited diabetes and deafness (MIDD).

! you have any of these symptoms after starting

metformin: seizure, declined cognitive abilities, difficulty with body movements, symptoms indicating nerve damage (e.g. pain or numbness), migraine and deafness.

Stop taking Metformin tablets for a short time if you have a condition that may be associated with dehydration

(significant loss of body fluids) such as severe vomiting, diarrhoea, fever, exposure to heat or if you drink less fluid than normal. Talk to your doctor for further instructions.

Stop taking Metformin tablets and contact a doctor or the nearest hospital immediately if you experience some of the symptoms of lactic acidosis, as this condition may lead to coma.

Symptoms of lactic acidosis include:

• vomiting
• stomach ache (abdominal pain)
• muscle cramps
• a general feeling of not being well with severe tiredness · difficulty breathing
• reduced body temperature and heartbeat. Lactic acidosis is a medical emergency and must be treated in a hospital.

If you need to have major surgery you must stop taking Metformin Tablets during and for some time after the procedure. Your doctor will decide when you must stop and when to restart your treatment with Metformin.

Metformin on its own does not cause hypoglycaemia (a blood glucose level which is too low). However, if you take Metformin together with other medicines to treat diabetes that can cause hypoglycaemia (such as sulphonylureas, insulin, meglitinides), there is a risk of hypoglycaemia. If you experience symptoms of hypoglycaemia such as weakness, dizziness, increased sweating, fast heart beating, vision disorders or difficulty in concentration, it usually helps to eat or drink something containing sugar.

During treatment with Metformin Tablets, your doctor will check your kidney function at least once a year or more frequently if you are elderly and/or if you have worsening kidney function.

Other medicines and Metformin Tablets

If you need to have an injection of a contrast medium that contains iodine into your blood stream, for example in the context of an X-ray or scan, you must stop taking Metformin before or at the time of injection. Your doctor will decide when you must stop and when to restart your treatment with Metformin.

Tell your doctor if you are taking, have recently taken or might take, any other medicines. You may need more frequent blood glucose and kidney function tests, or your doctor may need to adjust the dosage of Metformin Tablets. It is especially important to tell your doctor if you are taking: · medicines which increase urine production (diuretics) · medicines used to treat pain and inflammation (NSAID

and COX-2-inhibitors, such as ibuprofen and celecoxib) · certain medicines for the treatment of high blood

pressure (ACE inhibitors and angiotensin II receptor antagonists)

• beta-2- agonists such as salbutamol or terbutaline (used

  to treat asthma)

• corticosteroids (used to treat a variety of conditions, such

  as severe inflammation of the skin or in asthma) · medicines that may change the amount of Metformin in

  your blood especially if you have reduced kidney function (such as verapamil, rifampicin, cimetidine, dolutegravir, ranolazine, trimethoprim, vandetanib, isavuconazole, crizotinib, olaparib).

• other medicines used to treat diabetes

Metformin Tablets with alcohol

Avoid excessive alcohol intake while taking Metformin Tablets since this may increase the risk of lactic acidosis (see section 'Warnings and precautions).