Use and effectiveness of a two‐level initiation strategy for fixed‐dose prothrombin complex concentrate according to the initial international normalized ratio in an emergency department in Japan

Aim Prothrombin complex concentrate (PCC) was recently approved for patients on warfarin therapy with international normalized ratios (INRs) exceeding 2 in Japan. However, rapid normalization of INR is necessary even in patients who do not meet the aforementioned criteria. We previously found that a fixed PCC dose of 500 IU is insufficient in some patients with INR elevation but is effective in patients with INR less than 2.5. On the basis of the results, we revised the protocol to administer a PCC dose of 500 IU to patients with INR less than 2.5 or 1,000 IU to patients with higher INRs. This study aimed to validate this revised protocol at an emergency department (ED) in Japan. Methods We retrospectively collected data for all patients who received PCC in accordance with the revised protocol at our ED between October 2014 and December 2017 (period B) and compared the findings with those in the previous period (January 2013 to September 2014, period A). Results In total, 15 and 11 patients received PCC without complications during periods A and B, respectively. All but one patient obeyed the protocol during period B. The average INRs at baseline and within 120 min after PCC infusion were 2.58 and 1.39, respectively, in period A ( n = 9), versus 2.54 and 1.28, respectively, in period B ( n = 8). Significantly more patients exhibited optimal responses (INR < 1.35) during period B (7/8) than during period A (3/9, P = 0.049). Conclusion Our revised protocol effectively normalized INR.