Patient leaflet - Metformin Teva SR 1000 mg prolonged-release tablets
1. What Metformin Teva SR is and what it is used for
Metformin Teva SR prolonged-release tablets contain the active ingredient metformin hydrochloride and belong to a group of medicines called biguanides, used in the treatment of Type 2 (non-insulin dependent) diabetes mellitus.
Metformin Teva SR is used for the treatment of Type 2 diabetes when diet and exercise changes alone have not been enough to control blood glucose (sugar). Insulin is a hormone that enables body tissues to take glucose from the blood and to use it for energy or for storage for future use. People with Type 2 diabetes do not make enough insulin in their pancreas or their body does not respond properly to the insulin it does make. This causes a buildup of glucose in the blood which can cause a number of serious long-term problems so it is important that you continue to take your medicine, even though you may not have any obvious symptoms. Metformin Teva SR makes the body more sensitive to insulin and helps return to normal the way your body uses glucose.
Metformin Teva SR is associated with either a stable body weight or modest weight loss.
Metformin Teva SR prolonged-release tablets are specially made to release the drug slowly in your body and therefore are different to many other types of tablet containing metformin.
2. What you need to know before you take Metformin Teva SR
Do not take Metformin Teva SR
- if you are allergic to metformin or any of the other ingredients of this medicine (listed in section 6). An allergic reaction may cause a rash, itching or shortness of breath.
- if you have liver problems
- if you have severely reduced kidney function
- if you 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.
- if you have lost too much water from your body (dehydration). Dehydration may lead to kidney problems, which can put you at risk for lactic acidosis (see 'Warnings and precautions’).
- if you 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’).
- if you have been treated for acute heart problems or have recently had a heart attack or have severe circulatory problems or 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’).
- if you are a heavy drinker of alcohol.
- if you are under 18 years of age.
Warnings and precautions
Talk to your doctor before taking Metformin Teva SR
Risk of lactic acidosis
Metformin Teva SR 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.
Stop taking Metformin Teva SR 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 Teva SR 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.
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.
If you need to have major surgery you must stop taking Metformin Teva SR during and for some time after the procedure. Your doctor will decide when you must stop and when to restart your treatment with Metformin Teva SR.
Metformin taken alone doesn’t cause hypoglycaemia (blood sugar levels that are too low). However when it is used in combination with other medicines used to treat diabetes (e.g. sulphonylureas, insulin or meglitinides) there is a risk of hypoglycaemia. If you notice signs of hypoglycaemia (such as weakness, dizziness, increased sweating, fast heart beat, vision disturbances, or difficulty in concentration), eat or drink something with sugar.
During treatment with Metformin Teva SR, 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.
You may see some remains of the tablets in your stools. Do not worry - this is normal for this type of tablet.
You should continue to follow any dietary advice that your doctor has given you and you should make sure that you eat carbohydrates regularly throughout the day.
Do not stop taking this medicine without speaking to your doctor.
Children and adolescents
Children and adolescents should not use this medicine. It is not known if this medicine is safe and effective when used in children and adolescents under 18 years of age.
Other medicines and Metformin Teva SR
If you need to have an injection of a contrast medium that contains iodine into your bloodstream, in the context of an X-ray or scan, you must stop taking Metformin Teva SR before or at the time of injection. Your doctor will decide when you must stop and when to restart your treatment with Metformin Teva SR.
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 Teva SR. It is especially important to mention the following:
- Medicines which increase urine production (diuretics (water tablets) such as furosemide).
- 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)
- Steroids such as prednisolone, mometasone, beclometasone.
- Sympathomimetic medicines including epinephrine and dopamine used to treat heart attacks and low blood pressure. Epinephrine is also included in some dental anaesthetics.
- Medicines that may change the amount of Metformin Teva SR 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 Teva SR with alcohol
Avoid excessive alcohol intake while taking Metformin Teva SR since this may increase the risk of lactic acidosis (see section ‘Warnings and precautions’).
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.
Do not take Metformin Teva SR if you are breast-feeding.
Ask your doctor or pharmacist for advice before taking this medicine.
Driving and using machines
Metformin Teva SR taken on its own does not cause ‘hypos’ (symptoms of low blood sugar or hypoglycaemia, such as faintness, confusion and increased sweating) and therefore should not affect your ability to drive or use machinery.
You should be aware, however, that Metformin Teva SR taken with other antidiabetic medicines can cause hypos, so in this case you should take extra care when driving or operating machinery.
Metformin Teva SR contains sodium
This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium-free’.
3. How to take Metformin Teva SR
Your doctor may prescribe Metformin Teva SR for you to take on its own, or in combination with other oral antidiabetic medicines or insulin.
Always take Metformin Teva SR exactly as your doctor has told you.
You should check with your doctor or pharmacist if you are not sure.
Recommended dose
Usually you will start treatment with one 500 mg metformin prolonged-release tablet daily. After you have been taking metformin for about 2 weeks, your doctor may measure your blood sugar and adjust the dose. The maximum daily dose of metformin prolonged-release tablets is 2000 mg.
If you have reduced kidney function, your doctor may prescribe a lower dose.
How to take the tablets
Normally, you should take the tablets once a day, with your evening meal.
In some cases, your doctor may recommend that you take the tablets twice a day. Always take the tablets with food.
Swallow the tablets whole with a glass of water, do not chew, break or crush the tablets.
If you take more Metformin Teva SR than you should
If you take extra tablets by mistake you need not worry, but if you have unusual symptoms, contact your doctor. If the overdose is large, lactic acidosis is more likely. Symptoms of lactic acidosis are non-specific, such as vomiting, bellyache with muscle cramps, a general feeling of not being well with severe tiredness, and difficulty in breathing. Further symptoms are reduced body temperature and heart beat. If you experience some of these symptoms, you should immediately seek medical attention, as lactic acidosis may lead to coma. Stop taking Metformin Teva SR immediately and contact a doctor or the nearest hospital straightaway.
If you forget to take Metformin Teva SR
Take it as soon as you remember with some food. Do not take a double dose to make up for a forgotten dose.
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 Teva SR 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 Teva SR and contact a doctor or the nearest hospital immediately, as lactic acidosis may lead to coma.
Metformin Teva SR may cause abnormal liver function tests and hepatitis (inflammation of the liver) which may result in jaundice (may affect up to 1 user in 10,000). If you develop yellowing of the eyes and/or skin contact your doctor immediately.
Other possible side effects are listed by frequency as follows:
Very common (may affect more than 1 in 10 people)
- Diarrhoea, nausea, vomiting, stomach ache or loss of appetite. If you get these, do not stop taking the tablets as these symptoms will normally go away in about 2 weeks. It helps if you take the tablets with or immediately after a meal.
Common (may affect up to 1 in 10 people)
- Taste disturbance
- 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)
- Skin rashes including redness, itching and hives.
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 Teva SR
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 blister and carton after EXP. The expiry date refers to the last day of that month.
This medicinal product does not require any special storage conditions.
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 Teva SR contains
- The active substance is metformin hydrochloride. Each prolonged-release tablet contains 500 mg, 750 mg or 1000 mg of metformin hydrochloride corresponding to 390 mg, 585 mg or 780 mg metformin base.
- The other ingredients are magnesium stearate, silica colloidal anhydrous, carmellose sodium and hypromellose.
What Metformin Teva SR looks like and contents of the pack
Metformin Teva SR 500 mg prolonged-release tablets are white to off-white, capsule shaped tablets, 16.5 mm in length, 8.2 mm in width and 6.1 mm in thickness, debossed with ‘SR 500’ on one side and plain on other side.
Metformin Teva SR 750 mg prolonged-release tablets are white to off-white, capsule shaped tablets, 19.6 mm in length, 9.3 mm in width and 6.9 mm in thickness, debossed with ‘SR 750’ on one side and plain on other side.
Metformin Teva SR 1000 mg prolonged-release tablets are white to off-white, oval tablets, 22.0 mm in length, 10.5 mm in width and 8.9 mm in thickness, debossed with ‘SR 1000’ on one side and plain on other side.
Metformin Teva SR is available in blister packs containing 30 or 60 tablets.
Not all pack sizes may be marketed.
Marketing Authorisation Holder
Teva UK Limited, Ridings Point, Whistler Drive, Castleford, WF10 5HX, United Kingdom
Manufacturer
Teva Operations Poland Sp. z.o.o, ul. Mogilska 80, Kraków, 31-546, Poland
OR*
Balkanpharma-Dupnitsa AD, 3 Samokovsko Shosse Str., Dupnitsa, 2600, Bulgaria
This leaflet was last revised in 03/2025.
PL 00289/2159-2161
*Only the actual site of batch release will appear on the printed version of the leaflet.