It is an oral anticoagulant.

Indications: deep vein thrombosis, transient brain ischaemic attacks, prophylaxis with prosthetic heart valves.

Cautions: hepatic or renal disease, recent surgery; avoid crane berry juice, breast feeding.

Contra-indications: pregnancy, peptic ulcer, severe hypertension, bacterial endocarditis.

Side Effects: haemorrhage, hypersensitivity, alopecia, diarrhea, unexplained drop in hematocrit, ‘purple toes’, skin necrosis and hepatic dysfunction; also nausea and vomiting.

Dose: loading dose 10 mg daily for 2 days (5-6 mg if patient likely to be sensitive).

Maintenance, usually 3-9 mg from day 3, according to prothrombin time based on International Normalized Ratio (INR). doses are taken at the same time each day. The therapeutic range in prophylactic therapy of deep- vein thrombosis including high-risk surgery, 2-2.5 mg. Prophylactic therapy in hip surgery and fractured femur- operations, for treatment of deep vein thrombosis, pulmonary embolism, and transient ischaemic attacks, 2-3 mg per day. Recurrent deep-vein thrombosis and pulmonary embolism, arterial disease including myocardial infarction, arterial grafts, and prosthetic heart valves and grafts 3-4.5 mg per day.