Fixed-dose 4-factor prothrombin complex concentrate: we don't know where we're going if we don't know how to get there.

4-Factor Prothrombin Complex Concentrate (4F-PCC) is the standard-of-care intervention in patients with major bleeding taking oral vitamin K antagonists. Despite growing clinical experience with 4-FPCC, the optimal dosing strategy remains unclear. In balancing efficacy, safety, and cost of this treatment, many institutions have adopted a low, fixed-dose regimen, with average doses lower than that in the package insert. The fixed-dose 4F-PCC strategy is supported by the available observational studies and case reports; however, the current body of literature is highly heterogenous. The purpose of this narrative review is to address the advantages and shortcomings with clinical use of fixed-dose 4F-PCC, as well as limitations of the available literature. The heterogeneity of the current literature should guide future studies to support or refute this potentially life-saving intervention.