Full instructions, dosage information and potential known side effects are all available in the leaflet that comes with the prescription product. If you require any advice or assistance with placing your order, please donâ€™t hesitate to contact our team.
How do I take/use this medicine?
Take Warfarin exactly as directed by your doctor. Do not take more or less than instructed by your doctor.
Small changes in the dose of Warfarin can cause large changes in the thickness of your blood. It is important for you to follow the doctor's instructions very carefully. Your doctor may need to adjust your dose of Warfarin, especially in the first few months of treatment.
Warfarin must be taken exactly as directed for it to work well. Continue taking Warfarin even when you feel better. Warfarin is not a cure for your condition and you may need to take it for an indefinite length of time. Do not stop taking Warfarin unless instructed by your doctor.
You may take Warfarin with or without food. Try to take it at the same time each day.
What if my doctor has asked me to cut some of my tablets in order to make up a particular dosage?
If your doctor has instructed you to cut some of your tablets in order to make up a particular dosage, make sure you cut your tablets with a proper tablet cutter. Do not use any other tool to cut the Warfarin tablets. Only a proper tablet cutter is able to cut a tablet accurately in half. Cutting a tablet accurately is important in ensuring that you get an accurate dosage and this is especially important for Warfarin. A Warfarin tablet can only be cut along the score line. Do not cut it any other way.
DO NOT cut your Warfarin tablets unless you have been told to do so by your doctor.
What should I take note of while using/taking this medicine?
Inform your doctor if you have kidney or thyroid problems.
You may bleed more easily and for a longer time than usual while you are being treated with Warfarin. Alert your doctor if you notice excessive bleeding.
Do not take part in activities in which you may fall or get injured, such as contact sports. Report all falls and injuries -- especially head injuries and including even minor head trauma -- to your doctor. There could be internal bleeding which may not be obvious to you.
Take special care when shaving or handling sharp objects to avoid cutting yourself. Use a soft toothbrush when brushing your teeth to reduce the risk of gum bleeding.
Carry identification stating that you are on Warfarin. Most hospitals and clinics will be able to provide you with such an identification. Speak to your doctor about this.
Do not switch to another brand of Warfarin unless your doctor has instructed you to do so. Changing to a different brand of Warfarin may affect the control of your blood because the different brands do not have the same effectiveness.
Why do I need to have blood tests done so often?
For as long as you are taking Warfarin, you will need to have regular blood tests to check your body's response to the medicine. This blood test is called an INR (International Normalised Ratio). The INR measures how much time your blood takes to clot. Each person has his or her own target INR result. Your doctor will discuss with you about your target INR result.
You will need to have an INR blood test done more often in the first few days or weeks, so that your doctor can monitor your response to Warfarin and a suitable Warfarin dose can be customised for you. Warfarin doses will vary for different people as each person's physical condition is different.
Keep all appointments with your doctor as he needs to closely monitor your response to Warfarin and any side effects that Warfarin may cause. Make sure you have your blood tests done as scheduled by the doctor.
When should I not use this medicine?
Alert your doctor immediately if you have a history of any of these conditions:
- bleeding disorders, for example, haemophilia
- stomach ulcers, especially if you have ever bled from a stomach ulcer
- high blood pressure that is severe or not well-controlled
- liver problems
- heart disease
Inform your doctor if you have any other illnesses not included in this list.
Do not take Warfarin if you are pregnant or planning to have a baby soon. If you become pregnant while being treated with Warfarin, alert your doctor immediately. Warfarin may cause harm to your unborn child. Use proven birth control methods while being treated with Warfarin. You may wish to discuss birth control methods with your doctor.
Let your doctor know if you have recently had an operation.
If you are going for an operation, including minor operations and dental work, first consult your Warfarin doctor before going ahead with the operation or dental work. You must also inform the surgeon or dentist that you are taking Warfarin.
Are there any restrictions on the type of food I can take?
Avoid drastic changes to your usual diet.
Some types of food contain Vitamin K. Vitamin K can reduce the effect of Warfarin, especially when taken in large amounts.
Avoid taking unusually large amounts of food that is high in vitamin K. These include dark green vegetables, beef or pork liver and green tea. However, if it is your usual habit to take these foods, you may continue to do so. The key is to avoid sudden or drastic changes to your usual diet.
Avoid alcohol. Inform your doctor if you drink often, as alcohol consumption can affect the way Warfarin works in your body.
Why do I need this medicine?
Warfarin is a blood-thinning medicine which lowers the clotting ability of the blood.
Warfarin prevents harmful blood clots from forming in blood vessels and inside the heart. It also prevents blood clots that have already formed from growing larger, so that the clots can be easily dissolved by the body's natural clot-dissolving mechanism. Blood clots block the smooth flow of blood. Blood clots may also be loosened and flow to other parts of the body where they block the flow of blood to vital organs such as the heart or brain.
If a blood clot forms in a blood vessel that supplies the heart or brain, the heart or brain will not be able to get enough oxygen or nutrients. This results in a heart attack or a stroke. Heart attacks and strokes can also be caused by loose blood clots that originate from elsewhere in the body, such as the lower leg.
Warfarin is used after a heart attack to prevent blood clots from forming and causing another heart attack.
Warfarin is also used to prevent blood clots in people with artificial heart valves or those with faulty heart valves. It is also used to prevent blood clots in people who suffer from atrial fibrillation (AF) -- an illness in which the heart beats irregularly, causing blood to pool and clot in the heart.
Warfarin is also used to prevent blood clots from forming in the leg veins (deep vein thrombosis or DVT) and the vessels of the lungs (pulmonary embolism or PE).
What side effects could I experience?
Warfarin may cause you to bleed more easily. Inform your doctor if you have:
- unusual bleeding, especially excessive bleeding or bleeding that takes a long time to stop
- gum or nose bleeding that takes a longer than usual time to stop
- unusual bruises, especially if the bruises appear by themselves or if they cover a large area
- heavier than usual menstrual flow or any other changes in the menstrual flow
You should also inform your doctor if you have nausea, vomiting, diarrhoea, fever or other signs of infection that last for 2 days or more. These could affect the way Warfarin works in your body.
Inform your doctor quickly or go to the Emergency Department of the hospital if you:
- have any bleeding that does not stop
- have sticky, black or bloody bowel movements
- have blood in the urine (this usually shows as a dark tea colour)
- cough out blood or phlegm that looks like coffee grounds
- have severe dizziness
- have chest pain
- are short of breath
- have severe headache with nausea or vomiting or confusion
- have swelling, pain or tenderness in the abdominal area
- have purple discolouration of the skin, especially around the toes, feet and legs
- develop yellowing of the whites of the eyes or palms of your hands
You should also let your doctor know if you fall or injure your head or back. Also alert your doctor if you have any severe or prolonged back pain that has no obvious cause.
How should I store this medicine?
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.
Can I take/use this with other medicines?
Alert your doctor if you are taking or have taken any other medicines, especially those listed here. Some medicines may continue to affect the way Warfarin works in your body even if you have not been taking the medicine for some time.
- other blood thinning medicines such as aspirin, ticlopidine, clopidogrel, cilostazol, dipyridamole
- allopurinol (a gout medicine)
- cimetidine (a gastric medicine)
- amiodarone, propafenone (heart medicines)
- itraconazole, fluconazole, voriconazole (antifungal medicines)
- rifampicin (a TB medicine)
- phenytoin, carbamazepine (epilepsy medicines)
- painkillers such as paracetamol (long-term use)
- other painkillers such as diclofenac, mefenamic acid, ibuprofen and related medicines
- fluvastatin, simvastatin, lovastatin, rosuvastatin, clofibrate and related agents (cholesterol medicines)
- multivitamins containing vitamin K
- orlistat (a diet pill)
There are many other medicines and herbal products which interfere with Warfarin.
Always inform your doctor and pharmacist if you are taking any other medicines, including herbal tonics, supplements and medicines that you buy without a prescription.
Do not start to take other medicines, herbal preparations or supplements without informing your doctor and pharmacist.
Do not take antacids together with Warfarin. If you must take antacids, take them at least 1 hour before or 2 hours after you have taken Warfarin. Antacids can reduce the effectiveness of Warfarin when taken together.