It can, however, be useful in TIAs, particularly if aspirin treatment has not been successful, and is given as prophylaxis in atrial fibrillation. The typical induction dose is 10mg for two days, but this should be tailored to individual requirements. The maintenance dose is usually 3-9mg, taken at the same time each day. Patients should report nose bleeds without any apparent cause, black or red faeces and dark red or brown urine to the doctor. They are also advised to report skin rash, hair loss, nausea, vomiting, diarrhoea, fever, jaundice or breathing difficulties.
Warfarin is teratogenic.
The effects of warfarin are enhanced by large amounts of alcohol and may be reduced by increased dietary intake of fats and oils. Vitamin K is present in vegetables, so major changes in diet may also affect control, as may taking the vitamin in supplements. These are used to confirm diagnosis, as brain tumour and encephalitis can cause similar symptoms. It is best carried out in the first 48 hours after the stroke. Such investigations can differentiate between a stroke caused by infarction and one caused by bleeding.