Patient leaflet - Metformin Hydrochloride 1000 mg film-coated tablets
1. What Metformin Hydrochloride Tablets is and what it is used for
Metformin Hydrochloride Tablets contains metformin, 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 Hydrochloride Tablets helps to lower your blood glucose to as normal a level as possible.
If you are an overweight adult, taking Metformin Hydrochloride Tablets over a long period
of time also helps to lower the risk of complications associated with diabetes. Metformin Hydrochloride Tablets is associated with either a stable body weight or modest weight loss.
Metformin Hydrochloride Tablets 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 Hydrochloride Tablets on its own or together with other
medcines to treat diabetes (medicines taken by mouth or insulin).
Children 10 years and over and adolescents can take Metformin Hydrochloride Tablets
on its own or together with insulin.
2. What you need to know before you take Metformin Hydrochloride Tablets
Do not take Metformin Hydrochloride Tablets
if you are allergic (hypersensitive) to metformin or any of the other ingredients of this
medicine (see ‘What Metformin Hydrochloride Tablets contains’ in section 6) - 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 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 precau-tions').
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 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').
if you drink a lot of alcohol
If any of the above applies to you, talk to your doctor, before you start taking this medicine.
- 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 Tablets 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 Hydrochloride Tablets 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 Hydrochloride 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 Hydrochloride 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 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 Hydrochloride 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 Hydrochloride Tablets.
Metformin Hydrochloride Tablets on its own does not cause hypoglycaemia (a blood glucose level which is too low). However, if you take Metformin Hydrochloride Tablets 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 hypo-glycaemia such as weakness, dizziness, increased sweating, fast heart beating, vision disor-ders or difficulty in concentration, it usually helps to eat or drink something containing sugar. During treatment with Metformin Hydrochloride 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 Hydrochloride 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 Hydro-chloride Tablets before or at the time of injection. Your doctor will decide when you must stop and when to restart your treatment with Metformin Hydrochloride Tablets. 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 Hydrochloride Tablets. 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 angioten-
sin 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 Hydrochloride Tablets in your blood,
especially if you have reduced kidney function (such as verapamil, rifampicin, cimetidine, dolutegravir, ranolazine, trimethoprime, vandetanib, isavuconazole, crizotinib, olaparib). - other medicines used to treat diabetes.
Metformin Hydrochloride Tablets with alcohol
Avoid excessive alcohol intake while taking Metformin Hydrochloride Tablets 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.
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Driving and using machines
Metformin Hydrochloride Tablets 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 Hydrochloride Tablets 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.
3. How to take Metformin Hydrochloride Tablets
Always take Metformin Hydrochloride Tablets exactly as your doctor has told you. Check with your doctor or pharmacist if you are not sure.
Metformin Hydrochloride 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 500 mg or 850 mg Metformin Hydrochloride Tablets 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 Hydrochloride Tablets 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.
The score line is only there to help you break the tablet if you have difficulty swallowing it whole.
If you take insulin too, your doctor will tell you how to start Metformin Hydrochloride Tablets.
Monitoring
Your doctor will perform regular blood glucose tests and will adapt your dose of Metformin
Hydrochloride 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 Hydrochloride Tablets
Take Metformin Hydrochloride 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 Hydrochloride Tablets is too strong or too weak, talk to your doctor or pharmacist.
If you take more Metformin Hydrochloride Tablets than you should
If you have taken more Metformin Hydrochloride 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 Hydrochloride Tablets immediately and contact a doctor or the nearest hospital straight away.
If you forget to take Metformin Hydrochloride 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 product, ask your doctor or pharmacist.
4. Possible side effects
Like all medicines, Metformin Hydrochloride Tablets can cause side effects, although not everybody gets them. The following side effects may occur:
Metformin Hydrochloride Tablets 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 Hydrochloride Tablets 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 Hydrochloride Tablets. It helps if you spread the doses over the day and if you take Metformin Hydrochloride Tablets with or straight after a meal. If symptoms continue, stop taking Metformin Hydrochloride 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 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 Hydrochloride 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, 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 at: www.mhra.gov. uk/yellow card 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 medi-cine.
5. How to store Metformin Hydrochloride Tablets
Keep out of the sight and reach of children. If a child is treated with Metformin Hydrochloride Tablets, parents and caregivers are advised to oversee how this medicine is used. “Store below 25°C.”
Do not use Metformin Hydrochloride Tablets after the expiry date which is stated on the carton or the bottle or the blister after ‘EXP’. The expiry date refers to the last day of that month. Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how to dispose of medicines no longer required. These measures will help to protect the environment.
6. Contents of the pack and other information
What Metformin contains
- The active substance is metformin hydrochloride. Each film-coated tablet contains 1000 mg metformin hydrochloride.
The other ingredients are: Tablet core:
Starch Pregelatinized, Povidone K - 30, Povidone K - 90, Crospovidone XL 10, Magnesium stearate.
Film coating:
Hypromellose, Titanium Dioxide and Polyethylene glycol 400
This medicine is available in pack sizes
The tablets are supplied in Blister packs of 10's
What Metformin looks like and contents of the pack
Off-white, deep concave film coated tablets with debossed one side ‘S’ with break line and another side ‘M3’with break line.
Marketing Authorisation Holder
Farmak Pharmaceuticals UK Ltd
First Floor, 47 Queen Street, Hull, HU1 1UU, United Kingdom
Manufacturer
Ascenders consulting Services Limited, 110 Butterfield, Great Marlings, Luton, LU2 8DL, United Kingdom.
Marketing Authorisation Number: PL 59209/0044
This leaflet was last revised: June 2026
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