Skip to Content

UK Edition. Click here for US version.



View full screen / Print PDF » Download PDF ⇩
for alternative UK supply
Patient Information Leaflet
Metformin 500mg or 850mg Film-Coated Tablets

Read all of this leaflet carefully before you start taking this medicine.
- Keep this leaflet. You may need to read it again.
- If you have further questions, ask your doctor or your pharmacist.
- This medicine has been prescribed only for you. Do not pass it on to
others. It may harm them, even if their symptoms are the same as yours.
- If any of these side effects gets serious, or if you notice any side effects
not listed in this leaflet, please tell your doctor or pharmacist.


In this leaflet:
1. What metformin tablets are and what they are used for
2. Before you take metformin tablets
3. How to take metformin tablets
4. Possible side effects
5. How to store metformin tablets
6. Further information
1. What metformin tablets are and what they are used for
Metformin belongs to a group of medicines called biguanides. Metformin is used for the treatment of
"Type 2 diabetes" (non-insulin dependent diabetes).
How metformin works
- In type 2 diabetes, there is too much sugar (glucose) in your blood. This is because your body does
not make enough insulin or because it makes insulin that does not work properly.
- Insulin is a hormone that allows your body tissue to take glucose from the blood and use it for
energy or for storage for future use.
- Metformin works by improving the sensitivity of your body to insulin. It helps your body to use
glucose in the normal way again.
Using this medicine
• This medicine is given when diet and exercise alone has not been able to control your blood sugar
• Metformin can be given on its own. However, sometimes it is given with other medicines for diabetes
or with insulin.
• In patients who are overweight, long-term use of metformin also helps to lower the risk of any
problems related to diabetes.
2. Before you take metformin tablets
Do not take metformin tablets if:
• you are allergic (hypersensitive) to metformin or any of the other ingredients in these tablets (see
section 6: Further information). An allergic reaction can include a rash, itching or shortness of
• you have recently had a heart attack or any other heart problems
• you have severe circulation problems or difficulty in breathing
• you have liver or kidney problems
• you have recently had a severe infection, injury or trauma (shock)
• you are dehydrated
• you are a heavy drinker of alcohol (more than 21 units a week for a man or 14 units a week for a
woman). A unit is equivalent to a small glass of wine, one shot or half a pint of beer
• you have failed to respond to treatment with other anti-diabetic medicines called sulphonylureas
• you have an illness that started suddenly, such as a cold or the flu
• you have ever suffered a loss of consciousness due to a diabetic coma or pre-coma
• you are on a very low calorie diet (less than 1000 calories per day)
• you are pregnant, planning to get pregnant or are breast-feeding (see Pregnancy and
Take special care with metformin tablets if:
• you have a debilitated physical condition
• you are elderly.
Operations and tests while taking metformin tablets
• The amount of sugar in your blood or urine should be checked regularly. Your doctor will also check
your kidneys are working properly. This should be done at least once a year (more often if you are
elderly or have kidney problems).
• If you are having tests on the functioning of your liver.
• If you are going to have an X-ray, tell your doctor you are taking metformin. If this involves having a
dye injected, you must stop taking metformin. You must not start to take metformin again for 48
hours after the X-ray and only after your doctor has checked that your kidneys are working properly.
• If you are going to have an operation that needs a general, spinal or peridural anaesthetic, tell your
doctor you are taking metformin before the operation. You must stop taking metformin 48 hours
before your operation. You must not start to take metformin again for 48 hours after the operation
and only after your doctor has checked that your kidneys are working properly.
• The amount of vitamin B12 in your body should also be checked regularly.
Taking other medicines
Please tell your doctor or pharmacist if you are taking or have recently taken any other medicines,
including medicines obtained without a prescription. In particular tell your doctor or pharmacist if you
are taking any of the following:
• steroids (such as hydrocortisone, betamethasone, prednisolone) – used to treat inflammatory and
allergic disorders
• water tablets (diuretics such as furosemide, bendroflumethiazide)
• ACE-inhibitors (such as captopril, ramipril, lisinopril) – used for heart problems and high blood
• beta-blockers (such as atenolol) – used for high blood pressure
• disopyramide -used to treat seriously irregular heartbeat patterns
• other medicines for high blood pressure (such as clonidine, reserpine guanethidine, diazoxide)
• other anti-diabetic medicines (such as insulin)
• NSAIDs (such as aspirin) – used to treat pain and inflammation
• MAOI inhibitors (such as moclobemide) – used to treat depression
• lipid regulating medicines (such as clofibrate and nicotinic acid derivatives) - used mainly to treat
raised cholesterol
• oestrogen and progesterone (female) hormones (such as the “Pill,” hormone replacement therapy)
• thyroid hormones (such as thyroxine sodium) - used for under active thyroid glands
• antipsychotic medicines (such as chlorpromazine) - used in the treatment of schizophrenia
• H2 blockers (such as cimetidine) - used to heal stomach ulcers
• warfarin, dicumarol and phenprocoumone - used to thin the blood
• adrenaline and noradrenaline - used to treat conditions such as allergic reactions, heart attacks and
low blood pressure
Taking metformin tablets with food and drink
Do not drink alcohol or take medicines containing alcohol while taking metformin.
Pregnancy and Breast-feeding
Do not take this medicine and talk to your doctor if you are pregnant, planning to get pregnant or are
Driving and using machines
Do not drive or use any tools or machines when your blood sugar level is low (sometimes called
“hypo”). Signs include feeling faint, confused and sweaty. This can happen if metformin is taken with
other diabetic medicines.




Metformin Tablets 500 & 850mg - 28, 56 & 84 Tabs
Wockhardt UK
FP2038; FP2039; FP2815
for UK alternative
(w)148 x (h)420mm
XXXXX (Dummy)
8 pt.
Adobe Illustrator CS5
Arial Regular / Bold
28th April, 2016
R 1st PDF sent on

- 29TH APRIL 2016

CHANGE CONTROL : Version changes due to change in:
Changes in detail: • Regulatory text amends


3. How to take metformin tablets
Always take metformin tablets exactly as your doctor has told you. You should check with your doctor
or pharmacist if you are not sure.
Taking this medicine
• Take with or just after food. This lowers the chance of getting an upset
• Do not chew the tablets but swallow them whole with a glass of water.
• To obtain a tablet, press on the tablet from the blister (or bubble) side,
pushing it through the foil. Do not remove the tablet from the blister until
you are ready to take it.
• If you are taking insulin you should only start taking metformin tablets in
Adults and the elderly
• The usual starting dose is one or two 500mg tablets, or one 850mg tablet a day, which is gradually
increased until the right dose is found for you.
• Do not take more than a total of six 500mg tablets, or three 850mg tablets, in one day.
• In most cases the symptoms can eventually be controlled with three 500mg tablets, or two 850mg
tablets, a day.
• The daily doses should be divided into two or three doses.
Not for use in children.
If you take more metformin tablets than you should
Talk to a doctor or go to a hospital straight away. The following effects may happen:
• Unexpected weight loss, feeling very sick or being very sick, very fast breathing which you cannot
stop, stomach pains or feeling cold. You may have something called ‘lactic acidosis’. The doctor
may use a method called ‘haemodialysis’ to remove the extra lactate and metformin from your body.
If you forget to take metformin Tablets
Take them as soon as you remember. However, if it is almost time for the next dose, skip the missed
dose. Then go on as before. Do not take a double dose to make up for the forgotten dose.
If you stop taking metformin tablets
Keep taking this medicine until your doctor tells you to stop.
4. Possible side effects
Like all medicines, metformin can cause side effects, although not everybody gets them.
If you get any of the following very rare side effects, stop taking metformin and see your doctor
• unexpected weight loss
• feeling very sick (nausea) or being very sick (vomiting)
• very fast breathing which you cannot stop
• stomach pains or feeling cold
• muscle pains
• clouding of consciousness
This may mean you have something called “diabetic ketoacidosis” or “lactic acidosis”.
These can be signs of serious problems with your diabetes. If this happens, see a doctor as you will
need treatment straight away.
Other side effects:
Upset stomach, feeling sick (nausea), being sick (vomiting), diarrhoea (chronic diarrhoea may also
occur several years after starting the medicine), stomach ache, loss of appetite or the taste of metal in
your mouth. These side effects are most likely to happen at the start of treatment. They usually last for
a short time. It helps to take the dose with or after a meal.

Skin rash (including redness, itching or hives).
Bloating and flatulence
Reduction in red blood cells which can make the skin pale yellow and cause weakness or breathlessness
Weight loss
Hypoglycaemia (low blood sugar).
Liver inflammation and jaundice
Low blood pressure and low body temperature caused by altered blood chemistry and kidney failure.

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.
By reporting side effects you can help provide more information on the safety of this medicine.
5. How to store metformin tablets
• Keep out of the reach and sight of children.
• Do not store above 25°C. Keep this medicine in the package or container in which it was given to
you. Do not transfer to another container.
• Do not use after the expiry date, which is stated on the blister and carton EXP (month, year). The
expiry date refers to the last day of that month.
• Do not use metformin tablets if you notice that the appearance of your medicine has changed. Talk
to your pharmacist.
• 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. Further Information
What metformin tablets contain
The active substance is metformin hydrochloride.
The other ingredients are sodium starch glycollate (type A), maize starch, povidone K30, colloidal
anhydrous silica, magnesium stearate, methylhydroxypropylcellulose, titanium dioxide E 171,
propylene glycol E1520, polyethylene glycol 6000, and purifed talc E553 b.
What metformin tablets look like and contents of the pack
Metformin 500mg tablets are white, film coated, round, biconvex tablets with MET 500 on one side
and CP on reverse. Metformin 850mg tablets are white, film coated, round, biconvex tablets with MET
850 on one side and CP on reverse. They come in blister packs of 28 and 84 (500mg) tablets and 56
(850mg) tablets.
Marketing Authorisation Holder: Wockhardt UK Limited, Ash Road North, Wrexham, LL13 9UF, UK.
Manufacturer: CP Pharmaceuticals Limited, Ash Road North, Wrexham, LL13 9UF, UK.
Other formats:
To listen to or request a copy of this leaflet in Braille, large print or audio please call, free of charge:
0800 198 5000 (UK Only)
Please be ready to give the following information:
Product name

Reference number

Metformin 500 mg Film-Coated Tablets


Metformin 850 mg Film-Coated Tablets


This is a service provided by the Royal National Institute of Blind People.
The leaflet was last approved in: April 2016.


Expand view ⇕

Source: Medicines and Healthcare Products Regulatory Agency

Disclaimer: Every effort has been made to ensure that the information provided here is accurate, up-to-date and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This information has been compiled for use by healthcare practitioners and consumers in the United States. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective or appropriate for any given patient. If you have questions about the substances you are taking, check with your doctor, nurse or pharmacist.