Rowe AS, et al. - In this retrospective, multicenter cohort study, researchers compared the international normalized ratio normalization efficacy of activated prothrombin complex concentrates and 4-factor prothrombin complex concentrates and assessed the thrombotic complications in patients treated with these products for warfarin-associated hemorrhage, excluding those patients who received either agent for an indication other than warfarin-associated hemorrhage, pregnant, had a baseline international normalized ratio of less than 2, received a massive transfusion as defined by hospital protocol, received plasma for treatment of warfarin-associated hemorrhage, or were treated for an acute warfarin ingestion. Equal efficacy was demonstrated by a low, fixed dose of activated prothrombin complex concentrate when compared with a standard dose 4-factor prothrombin complex concentrate for normalization of international normalized ratio. No increase in thrombotic events was seen.