See above for treatment targets and advice on starting warfarin.
- By mouth, usual daily dose in the range of 2-9 mg.
- 0.5 mg tablets are white
- 1 mg tablets are brown
- 3 mg tablets are blue
- 5 mg tablets are pink
- See treatment of bleeding in heparin for management of severe bleeding.
- Remember, warfarin does not usually cause bleeding but makes what would ordinarily be trivial bleeding worse. If there is bleeding, investigate the cause.
- Excessive anticoagulation is usually the result of a failure to take account of a factor that will enhance the anticoagulant effect of warfarin:
- The patient has a severe intercurrent illness and the dose of warfarin is not reduced.
- A drug that enhances the action of warfarin is started.
- A drug that reduces the effect of warfarin is stopped.
- The maintenance dose is incorrect, but the INR has not been measured.
- INR >8.0
- No bleeding. Stop warfarin and restart at a lower dose once the INR is <5.0.
- If the patient is at high risk of bleeding consider giving 0.5 mg vitamin K1 iv or 5 mg by mouth.
- INR 5.0-8.0
- No bleeding. Stop warfarin and restart at a lower dose once the INR is <5.0.
- INR >0.5 units above target but <5.0
- No bleeding. Continue warfarin at a lower dose.
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