FAQs
Should Fresh Frozen Plasma Be Used to Reverse the Effects of Warfarin?
The Answer: "Sometimes"
The patient who is over-anticoagulated with warfarin (whether bleeding or not) can present a significant challenge. As you probably know, warfarin acts by inhibiting the gamma carboxylation of factors II, VII, IX, and X (the vitamin K dependent factors) in the liver. In order to reverse the anticoagulation, either the blockage to production must be removed or sufficient quantities of the actual factors must be supplied. The best strategy depends on whether or not the patient is bleeding.The following is summarized from the excellent recommendations made in 2008 in the journal Chest (see Chest 133:160S-198S).
The first step (in patients who are not actively bleeding), in the correction of warfinin overcoagulation is simple: Hold the next dose of warfarin! In patients who are mildly anticoagulated (INR <5.0), this intervention alone is often enough to get the patient back to a more acceptable range.
If the INR is more significantly elevated (>5.0), however, the mainstay of therapy (in addition to holding the next warfarin dose) is vitamin K, which overcomes the drug-induced blockage and allows the factors listed above to be produced in normal forms. Vitamin K is typically administered orally in this situation, and it works great! Please note that in these recommendations, FFP is NOT indicated, no matter how high the INR, if the patient is not bleeding!
In a bleeding patient that is over-anticoagulated, the intervention, by design, becomes more aggressive. In addition to holding the next warfarin dose (obviously), the vitamin K should be administered intravenously. There are some clinicians that don't like that idea due to cases of anaphylaxis that have been reported, but most have used IV vitamin K successfully. Obviously, absorption is not an issue when an intravenous dose is given, but it still takes awhile for the liver to replenish the depleted vitamin K-dependent factors sufficiently to make a difference. Most of the time, IV vitamin K takes about 6 hours to work.
However, the recommendations also allow for the use of blood products to immediately correct the factor levels, if necessary. FFP is a good choice in this situation, at standard doses of 10-20 ml/Kg (note that in most patients, this will be FAR more than the typical two units that are requested by most clinicians). You should also note, however, that infusion of prothrombin complex concentrate (PCC) may be an even better option than FFP in this situation, as PCC contains the specific factors needed to correct the anticoagulation, and nothing else. Again, people get nervous about PCC because many remember the reports of thrombosis that occurred with the activated form of PCC, but most consider PCC safe currently. Recombinant activated factor VII concentrate (better known by most as ("NovoSeven") is also recommended for consideration in this circumstance.