Previous studies have shown fixed-dose 4PCC to be as effective as standard-dose 4PCC for warfarin reversal. However, certain patient populations such as those with high total body weight (TBW) or elevated baseline INR may be at increased risk for treatment failure. The purpose of this study was to validate the efficacy of a novel fixed-dose 4PCC protocol for warfarin reversal.

This was a multi-centered observational comparison of patients who received 4PCC for warfarin reversal. Fixed-dose patients received 1500 units of 4PCC with the dose increased to 2000 units in patients with a baseline INR ≥ 7.5, a TBW ≥ 100 kg, or for intracranial hemorrhage (ICH). Standard-dosing followed manufacturer recommendations. The primary outcome was achievement of a post-4PCC INR of ≤1.4. Secondary outcomes included target INR achievement among patients with a baseline INR ≥ 7.5, a TBW ≥ 100 kg, or neurologic bleeding indications; hospital length of stay; cost of therapy; and thromboembolic complications.

A total of 116 patients were included in the standard-dose group and 75 in the fixed-dose group. There was no difference in the primary outcome (65% vs 57%, p = 0.32). There was no difference in secondary outcomes aside from cost of therapy in which fixed-dose 4PCC was less expensive than standard-dose 4PCC.

A fixed-dose 4PCC regimen for warfarin reversal of 1500 units, with an increased dose of 2000 units for select patients, is as effective as standard-dose 4PCC for INR reversal.