Before you begin using a medication, be sure to inform your doctor of any medication conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Bleeding: The most serious risk associated with warfarin is bleeding in any tissue or organ. The risk of bleeding is related to the level of intensity and the duration of treatment.
It is extremely important to have regular blood tests (as recommended by your doctor) to ensure that the correct level of blood thinning is occurring. These blood tests measure your INR level to determine the dose of warfarin. Your health care provider will adjust the dose of warfarin depending on the INR level to ensure you are not receiving too little medication (which may result in blood clots forming) or too much medication (which may result in bleeding).
Medical conditions and other medications: If you have other medical conditions and are taking medications, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Some conditions and medications affect the way warfarin works and may affect the dosing of warfarin. Your doctor will recommend you get regular lab tests done.
NSAIDs: It is recommended that anyone taking nonsteroidal anti-inflammatory agents (NSAIDs) such as acetylsalicylic acid (ASA) or ibuprofen should be closely monitored to ensure that no change in anticoagulation dosage is required. NSAIDs can cause stomach ulcers or bleeding.
Purple toes syndrome:
Purple toes syndrome is a complication of warfarin treatment and consists of a dark, purplish or mottled colour of the toes, usually occurring 3 to 10 weeks (or later) after starting treatment with warfarin. Major features of this syndrome include:
- increasing and decreasing of the colour over time
- pain and tenderness of the toes
- purple colour of bottom surfaces and sides of the toes that turns white under moderate pressure and fades with elevation of the legs
Inform your doctor at once if you notice these symptoms.
Pregnancy: Warfarin should not be used during pregnancy. It passes through the placental barrier and may cause bleeding in the unborn baby. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: It is not known if warfarin passes into human breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of this medication have not been established for children less than 18 years of age. However, the use of warfarin by children is necessary in certain situations.