Ofek, F., Bar Chaim, S., Kronenfeld, N., et al. (2017) International Normalized Ratio Is Significantly Elevated with Rivaroxaban and Apixaban Drug Therapies: A Retrospective Study. Clinical Therapeutics, 39, 1003-1010.
https://doi.org/10.1016/j.clinthera.2017.04.007

has been cited by the following article:

• TITLE: Supratherapeutic International Normalized Ratio with Concomitant Warfarin and Cupric Chloride (Copper) Therapy

  AUTHORS: Jan Maxa, Rashed Khaleque, Scott Massey

  KEYWORDS: Warfarin, Copper, Supratherapeutic International Normalized Ratio

  JOURNAL NAME: Case Reports in Clinical Medicine, Vol.14 No.7, July 14, 2025

  ABSTRACT: We report a case of supratherapeutic international normalized ratio values in a hospitalized patient started on warfarin to prevent recurrent deep vein thrombosis. Her medical history showed a failed course of apixaban and so warfarin therapy was initiated during this admission but quickly stopped after sudden, significant increases in international normalized ratio for several days after termination of therapy. A review of any drug-drug interaction did not expose any reported interactions between warfarin and her current medications at that time. However, the concurrent administration of cupric chloride did raise the possibility of an undocumented interaction between these two entities. The pharmacokinetic/pharmacodynamic properties of both drugs provided a study into the consequences of a combination therapy, beyond the anticipated outcome, which is normally based on previously observed results.