Warfarin belongs to the group of medicines known as anticoagulants.
It is used to prevent and treat the formation of harmful blood
clots within the body by reducing the effects of vitamin K, which
is a vitamin present in the body, essential in the process of
blood-clotting. Warfarin is available in tablet form and is sometimes
known as: Marevan. You may notice the use of either of these names
on the packaging of your medicine.
Before taking Warfarin
Before taking warfarin make sure your doctor or pharmacist knows:
• if you are pregnant, trying for a baby or breast-feeding
• if you suffer from liver or kidney problems
• if you have recently had surgery of any kind or recently
had a baby
• if you have a stomach ulcer or have ever had a stomach
• if you suffer from any unusual bruising or bleeding
• if you suffer from uncontrolled hypertension (high blood
• if you suffer from an infection of the tissues surrounding
the heart called bacterial endocarditis
• if you have ever had an allergic reaction to this or
any other medicine
• if you are taking any other medicines, including those
available to buy without a prescription, herbal and complementary
How to take Warfarin
• Always read the manufacturer's information leaflet, if
possible, before beginning treatment.
• Take warfarin exactly as directed by your doctor or anticoagulant
• Do not stop taking warfarin without speaking to your
• You should have been given a treatment booklet with your
tablets. Read and follow the instructions carefully before beginning
• Warfarin is for you. Never give it to others, even if
their condition appears to be the same as yours.
• Never take more than the prescribed dose. If you suspect
that you or someone else has taken an overdose of Warfarin contact
your doctor or go to the accident and emergency department of
your local hospital at once. Always take the container with you,
if possible, even if it is empty.
Getting the most from your treatment
• Before taking any 'over-the-counter' medicines, always
check with your pharmacist which medicines are safe for you to
take alongside warfarin.
• Do not take medicines containing aspirin unless prescribed
by your doctor.
• Always attend your regular appointments with the doctor
or anticoagulant clinic. You will need to have regular blood tests,
especially during the first few weeks of treatment, to ensure
that the dose of warfarin you are taking is correct for you.
• You should carry your treatment booklet with you at all
times, ideally in your wallet or purse.
• Before having any kind of surgery, including dental or
emergency treatment, tell the doctor, dentist or surgeon you are
taking warfarin and show the person carrying out the tests or
treatment, your warfarin treatment booklet.
• Warfarin is used to prevent blood clots forming and therefore
thins the blood, it is important that you take care not to knock,
cut or bruise yourself while you are taking warfarin. Inform your
doctor if you suffer any falls, blows or injuries. You should
also take special care when brushing your teeth or shaving. Use
a soft toothbrush, be gentle when using dental floss and if possible
use an electric razor.
• Changing your diet suddenly can affect your warfarin
levels, especially if you begin to eat more vegetables and salad
or if you change the amount of fatty foods you have been eating.
You should not begin a weight reducing diet without discussing
it with your doctor first.
• Avoid drinking cranberry juice while you are taking this
medicine as it may affect the levels of warfarin in your body.
• Alcohol should only be drunk in moderation. Alcohol can
also affect the levels of warfarin in your body.
Can Warfarin cause problems?
As well as their useful effects all medicines can cause unwanted
side effects. Speak to your doctor or pharmacist if any of the
following side effects continue or become troublesome.
Skin rashes, thinning of the hair, diarrhoea, purple toes, feeling
or being sick.
Important: If you notice any unusual bruising, bleeding, blood
in the urine, blackened stools or jaundice (yellowing of the skin
and whites of the eyes) contact your doctor or anticoagulant clinic
If you experience any other worrying or troublesome side effects,
which you think may be due to this medicine, discuss them with
How to Store Warfarin
• Keep all medicines out of the reach of children.
• Store in a cool, dry place away from direct heat and
• Never keep out of date or unwanted medicines. Either
discard them safely out of the reach of children or take them
to your local pharmacist who will dispose of them for you.