Evidence-based On-call

Warfarin

Starting treatment
Indications
Dosing and monitoring
Complications
Follow-up

Follow-up

Advise your patient about the risk of bleeding, but indicate that serious bleeds are rare ^b

Note:

10% of patients on warfarin have one bleed per year (95% CI: 8.7% to 10%); 3% of patients have a major bleed (2.5% to 3.5%) ^b

Major bleeding and intracranial haemorrhage are uncommon

Indication	Regimen	Duration of anticoagulation	Major bleed/ year	Intracranial haemorrhage / year
atrial fibrillation ^a ^b	warfarin	indefinite	~ 2 to 3%	~1%
first DVT ^b	heparin and warfarin	six months	~3%	-
recurrent DVT ^b	heparin and warfarin	indefinitely	~2%	-

Expiry date: May 2003
Levels of Evidence used in grading these guides

With thanks to Drs. David Keeling, John Reynolds, David Sackett, Sharon Straus and Alan Townsend
for use of their anticoagulation guide on which this one is based.

Author	CM Ball
Reviewer	A Gallus
CAT Writer	CM Ball