METFORMIN 500MG TABLETS BP METFORMIN 850MG TABLETS BP – patient leaflet, side effects, dosage

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

Metformin is a medicine to treat diabetes. It 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 Tablets helps to lower your blood glucose to as normal 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 Tablets are 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 these Tablets if you:

• are allergic to Metformin or any of the other ingredients of this medicine (listed in section 6) • have liver problems or severely reduced kidney function

• have uncontrolled diabetes, with, for example, severe hyperglycaemia (high blood glucose), nausea, vomiting, diarrhoea, rapid weight loss, lactic acidosis (see “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 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 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 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.

Please note the following particular risk of lactic acidosis: 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 hydrochloride 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

Talk to your doctor or pharmacist before taking Metformin.

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 diseases).

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 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 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 in 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 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 Tablets on their own does not cause hypoglycaemia (a blood glucose level which is too low). However, if you take Metformin Tablets together with other medicines to treat diabetes that can cause hypoglycaemia (such as sulfonylureas, 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 if you eat or drink something containing sugar.

During treatment with Metformin, 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

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines.

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

You may need more frequent blood glucose and kidney function tests, or your doctor may need to adjust the dosage of Metformin. It is especially important to mention the following:

• 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 with food drink and alcohol

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

Pregnancy and breast-feeding

If you are pregnant or breast feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.

• 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.
• Do not take this medicine 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 these tablets together with other medicines to treat diabetes that can cause hypoglycaemia (such as sulfonylureas, insulin, meglitinides). Symptoms of hypoglycaemia include weakness, dizziness, increased sweating, fast heart beat, vision disorders or difficulty in concentration. Do not drive or use machines if you start to feel these symptoms. 30 mm

530 x 180 mm

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Information on sodium content

This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially “sodium free”.

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 Tablets 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 500mg or 850mg once a day. The maximum daily dose is 2000mg 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 500mg or 850mg 2 or 3 times a day. The maximum daily dose is 3000mg 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 Tablets.

Monitoring

• Your doctor will perform regular blood glucose tests and will adapt your dose of Metformin Tablets to your blood glucose levels. Make sure that you talk to your doctor regularly. This is particularly important for children and adolescents 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 the tablets 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 Tablets 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 Tablets 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 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 stop taking Metformin Tablets

Do not stop taking these tablets without consulting your doctor. Treatment should continue for as long as your doctor feels it is needed.

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

4. Possible side effects

Like all medicines, this medicine may 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 in 10,000 people), 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.

Other side effects

Very common: may affect 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 Tablets. It helps if you spread the doses over the day and if you take the tablets with or straight after a meal. If symptoms continue, stop taking Metformin Tablets and talk to your doctor.

Common: may affect up to 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: may affect up to 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 vomiting, bellyache (abdominal pain) with muscle cramps, a general feeling of not being well with severe tiredness and difficulty in breathing.
• skin reactions such as redness of the skin (erythema), itching or an itchy rash (hives).
• 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 this medicine.

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 Website: 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. If a child is treated with Metformin, parents and care giver are advised to oversee how this medicine is used.

• Blisters: Do not store above 25^OC. Store in the original package. Keep the blister in the outer carton.

  Containers :Do not store above 25^OC. Store in the original container. Keep the container tightly closed. • Do not use this medicine after the expiry date which is stated on the carton after EXP. The expiry date refers to the last day of that month.

  • 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
• The other ingredients are: Sodium starch glycolate, Colloidal anhydrous silica, Maize starch, Povidone and Magnesium stearate in the tablet core; the film coat contains Hypromellose, Titanium dioxide (E171), Propylene glycol, Purified talc and Macrogol 6000.

What Metformin Tablets look like and contents of the pack

• Tablets are white round, biconvex, film coated tablets debossed with ‘500’ or ‘850’ on one face and plain on the other. • Metformin tablets are available in packs of 14, 28, 56 or 84 tablets or containers containing 100, 250, 300 or 500 tablets. • Not all pack sizes may be marketed.

Marketing Authorisation Holder and Manufacturer

Name and address:

Bristol Laboratories Ltd,

Unit 3, Canalside, Northbridge Road, Berkhamsted,

Hertfordshire, HP4 1EG, United Kingdom.

Telephone: 0044 (0)1442 200922

E-mail: info@bristol-labs.co.uk

Manufacturer

Bristol Laboratories Ltd.

Laporte Way, Luton,

LU4 8WL, United Kingdom.

Manufacturer

Bristol Laboratories Ltd,

Unit 5, Traynor Way, Whitehouse Business Park,

Peterlee, SR8 2RU, United Kingdom.

Metformin 500mg tablets; PL 17907/0080

Metformin 850mg tablets; PL 17907/0081

This leaflet was revised in February 2025

To request a copy of this leaflet in Braille, large print or audio format, please contact the marketing authorisation holder at the address (or telephone, email) above.

V20 18-02-25 D0