Warfarin for VTE treatment

Warfarin is the preferred oral anticoagulant to treat venous thromboembolism (VTE) (ie deep vein thrombosis [DVT] or pulmonary embolism [PE]) in patients with concomitant severe kidney impairment or another indication for warfarin (eg antiphospholipid syndrome).

If using warfarin to treat VTE, give a parenteral anticoagulant concurrently when starting warfarin therapy (see Parenteral anticoagulants for VTE treatment for dosages). This overcomes the delay in achieving therapeutic anticoagulation and the initial increase in prothrombotic potential associated with starting warfarin. Warfarin started alone is associated with a high rate of thrombus extension.

Follow a local protocol to determine the warfarin dose. If a local protocol is not available, use (with a parenteral anticoagulant):

warfarin orally, daily, with dose adjusted to a target INR of 2 to 3 (see Age-adjusted protocol for starting warfarin for an example of an age-adjusted protocol for starting warfarin). warfarin warfarin warfarin

Monitor international normalised ratio (INR) daily and adjust the warfarin dose until the target INR is reached. Continue parenteral anticoagulant therapy for a minimum of 5 days and until the INR has been more than 2 on 2 consecutive days, then stop the parenteral anticoagulant and continue warfarin alone.

For duration of anticoagulant therapy to treat VTE, see Duration of anticoagulant therapy for VTE.

For information about dosing, monitoring and management of bleeding and overanticoagulation, see Practical information on using warfarin.