Evidence-based On-call

Deep vein thrombosis

Therapy

In addition ^a

give warfarin ^a

e.g. 5 mg ^a

at 1800 ^c

as soon as deep vein thrombosis has been demonstrated. ^a

Why?

Heparin and warfarin together is safer than warfarin alone. Patients who remain on heparin while awaiting satisfactory oral anticoagulation with warfarin have fewer recurrent symptomatic DVT. ^a
The effect on major bleeding is unclear. ^a

Starting anticoagulation with heparin and warfarin reduces symptomatic recurrent DVT

Patient	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNT (95% CI)
proximal DVT ^a	heparin and warfarin	warfarin alone	symptomatic recurrent DVT at 6 months	20%	13% (1.4% to 25%)	8 (4 to 71)

A loading dose of 5 mg of warfarin leads to more successful anticoagulation than a loading dose of 10 mg. ^a

More patients given a loading dose of 5 mg of warfarin are therapeutically stable after 5 days

Patient	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNT (95% CI)
starting anticoagulation ^a	5 mg loading dose of warfarin	10 mg loading dose of warfarin	INR 2.0 to 3.0 on 2 consecutive days, and never > 3.0 at 5 days	68%	190% (27% to 540%)	2 (1 to 5)