Warfarin

Dosing

1. Day 1: 5 to 7.5 mg po at night (to ensure absorption on an empty stomach),
2. Day 2, 3, 4...: 2.5 to 7.5 mg po qhs (most often 5 mg)

• An increase in INR of >0.3-0.4 units per day necessitates dose reduction
• CHF, liver disease, Vitamin K def, drugs may influence warfarin response

Range (INR)

2.5 to 3.5: mechanical prosthetic valves or recurrent thromboembolism

2.0-3.0: all other indications

Reversal

1. FFP (10-20/kg) to decr INR to 1.5 (should occur in 6-24 hr)
2. +/- Vitamin K (10 mg IM) (takes 24hrs to affect & 2wk to wear off)

Source

1/26/06 DONALDSON (addapted from Lampe), EMP 1/11