title: Persistent drug interaction between aprepitant and warfarin in patients receiving anticancer chemotherapy.
abstract: METHODS
  We describe two cases in which treatment with aprepitant persistently altered antithrombotic control in patients receiving warfarin. A 60-year-old man received 5 weekly cycles of chemotherapy. Aprepitant was administered as a 3-day regimen from the second cycle of chemotherapy. In each of the chemotherapy cycles that included aprepitant, the therapeutic international normalized ratio (INR) decreased markedly to <1.6, and slowly recovered over several weeks. A 47-year-old woman was treated with 4 weekly cycles of chemotherapy. Aprepitant was administered as a 3-day regimen. On day 8 of the first cycle of chemotherapy, the patient's INR fell markedly to 1.1. Although warfarin dosage was steadily increased over the four subsequent cycles of chemotherapy, therapeutic target range was not recovered. INR gradually returned to normal during the 2 months after the final cycle of chemotherapy.
  
  
  CONCLUSIONS
  To our knowledge, this is the first case report to document the effects of aprepitant in cancer patients receiving anticoagulation therapy.
authors.affiliation: Department of Pharmacy, Faculty of Medicine, The University of Tokyo Hospital, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan, yohno-tky@umin.ac.jp.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ohno
authors.forename: Maiko
authors.initials: M
authors.lastname: Yamada
authors.forename: Ryo
authors.initials: R
authors.lastname: Yamaguchi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hisaka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Suzuki
mesh_terms: D000925:Anticoagulants / Q000009:adverse effects / Q000097:blood; D000932:Antiemetics / Q000009:adverse effects / Q000097:blood; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000097:blood*; D000077608:Aprepitant; D004347:Drug Interactions / Q000502:physiology; D005260:Female; D006801:Humans; D019934:International Normalized Ratio / Q000639:trends; D008297:Male; D008875:Middle Aged; D009025:Morpholines / Q000009:adverse effects / Q000097:blood*; D014859:Warfarin / Q000009:adverse effects / Q000097:blood*
chemical_list: D000925:Anticoagulants; D000932:Antiemetics; D009025:Morpholines; D000077608:Aprepitant; D014859:Warfarin