Metformin SR 1000 mg prolonged release tablets – patient leaflet, side effects, dosage

1. What Metformin SR is and what it is used for

Metformin 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 SR is used together with diet and exercise to lower the risk of developing Type 2 diabetes in overweight adults, when diet and exercise alone for 3 to 6 months have not been enough to control blood glucose (sugar). You are at high risk of developing Type 2 diabetes if you have additional conditions like high blood pressure, age above 40 years, an abnormal amount of lipids (fat) in the blood or a history of diabetes during pregnancy.

The medicine is particularly effective if you are aged below 45 years, are very overweight, have high blood glucose levels after a meal or developed diabetes during pregnancy.

Metformin 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 build-up 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 SR makes the body more sensitive to insulin and helps return to normal the way your body uses glucose.

Metformin SR is associated with either a stable body weight or modest weight loss.

Metformin 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 SR

Do not take Metformin SR if you:

• are allergic to metformin hydrochloride or to any of the other ingredients of this medicine (listed in section 6). An allergic reaction may cause a rash, itching or shortness of breath
• 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 “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
• 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').
• 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)
• 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)
• are a heavy drinker of alcohol
• are under 18 years of age.

Warnings and precautions

Risk of lactic acidosis

Metformin 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 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 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.

If you need to have major surgery, you must stop taking Metformin 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 SR.

During treatment with Metformin 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.

If you are older than 75 years, treatment with Metformin SR should not be started to lower the risk of developing type 2 diabetes.

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.

Other medicines and Metformin SR

If you need to have an injection of a contrast medium that contains iodine into your bloodstream, for example in the context of an X-ray or scan, you must stop taking Metformin SR before or at the time of injection. Your doctor will decide when you must stop and when to restart your treatment with Metformin 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 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 SR in your blood, especially if you have reduced kidney function (such as verapamil, rifampicin, cimetidine, dolutegravir, ranolazine, trimethoprim, vandetanib, isavuconazole, crizotinib, olaparib).

Metformin SR with alcohol

Avoid excessive alcohol intake while taking Metformin 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.

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 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.

However, take special care if you take Metformin SR with other antidiabetic medicines that can cause hypos glycaemia (such as sulphonylureas, 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.

3. How to take Metformin SR

Your doctor may prescribe Metformin SR for you to take on its own, or in combination with other oral antidiabetic medicines or insulin.

Always take Metformin SR exactly as your doctor has told you.

10 0000 0 000000 Metformin SR 750 mg/ 1000 mg

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Metformin SR

750 mg/ 1000 mg

INP172 10 000 00 000000 You should check with your doctor or pharmacist if you are not sure. Swallow the tablets whole with a glass of water, do not chew.

Recommended dose

Usually, you will start treatment with 500 milligrams daily. After you have been taking Metformin SR for about 2 weeks, your doctor may measure your blood sugar and adjust the dose. The maximum daily dose is 2000 milligrams of Metformin SR.

If you have reduced kidney function, your doctor may prescribe a lower dose. 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.

If you take more Metformin 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 SR immediately and contact a doctor or the nearest hospital straightaway.

If you forget to take Metformin SR

Take it as soon as you remember with some food. Do not take a double dose to make up for a forgotten dose.

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 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 SR and contact a doctor or the nearest hospital immediately, as lactic acidosis may lead to coma.

Other possible side effects are listed by frequency as follows:

Very common side effect (may affect more than 1 in 10 people):

• Digestive problems such as diarrhoea, nausea, vomiting, stomach ache or loss of appetite. These side effects most often happen at the beginning of the treatment with Metformin SR. It helps if you take the tablets with or immediately after a meal. If symptoms continue, stop taking Metformin SR and talk to your doctor.
• Common side effects (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 side effects (may affect up to 1 in 10,000 people):

• lactic acidosis. This is a 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 SR and talk to your doctor.
• Skin rashes including redness, itching and hives.

Reporting of side effects

If you get any side effects, talk to your doctor, pharmacist or nurse. 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 SR

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

This medicine does not require any special storage conditions.

Do not swallow the desiccant.

Do not use this medicine after the expiry date which is stated on the label and 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 to protect the environment.

6. Contents of the pack and other information

What Metformin SR contains

Each prolonged-release tablet contains 750mg or 1000mg of the active ingredient metformin hydrochloride. The other ingredients are cellulose microcrystalline, hypromellose K 100M Premium CR, silica colloidal anhydrous and magnesium stearate.

What Metformin SR looks like and contents of the pack

Metformin SR 750mg are white to off-white, biconvex, oblong shaped, uncoated tablets, approximately 19.2 mm × 9.3 mm, debossed with ‘FN2’ on one side and plain on other side.

Metformin SR 1000mg are white to off-white, biconvex, oblong shaped, uncoated tablets, approximately 22.2 mm × 11.0 mm, debossed with ‘FN3’ on one side and plain on other side.

Metformin SR is supplied in HDPE bottle in the following packs size of 30 prolonged-release tablets.

Not all pack sizes may be marketed.

Marketing Authorisation Holder and Manufacturer

Accord Healthcare Limited

Sage House, 319 Pinner Road

North Harrow, Middlesex

HA1 4HF, United Kingdom

This leaflet was last revised in October 2023.