title: Low-dose fluconazole therapy potentiates the hypoprothrombinemic response of warfarin sodium.
abstract: BACKGROUND
  Fluconazole has been reported to interact with many medications. This study examined the effect of low-dose fluconazole therapy on the hypoprothrombinemic response of warfarin sodium in patients.
  
  
  METHODS
  Patients receiving low-intensity anticoagulation therapy with warfarin were recruited. All patients were taking stable doses of warfarin and had two baseline prothrombin times (PTs) within 10% of each other. Each patient received 100 mg of fluconazole daily for 7 days. Prothrombin times were measured on days 2, 5, and 8 during fluconazole administration.
  
  
  RESULTS
  All patients had a progressive increase in PTs. Mean (+/- SD) of PTs increased from 15.8 +/- 1 seconds before the administration of fluconazole to 18.9 +/- 1.9 seconds on day 5 and 21.9 +/- 2.2 seconds on day 8. Fluconazole therapy was stopped early in the three patients due to high PTs. The largest change in PT was 9.7 seconds. No bleeding was noted during the study.
  
  
  CONCLUSIONS
  Fluconazole predictably potentiates the hypoprothrombinemic response of warfarin. Prothrombin times must be monitored when fluconazole is administered to patients taking warfarin.
authors.affiliation: Pharmacy Service, Veterans Affairs Medical Center, Mountain Home, Tenn.
authors.forename: L L
authors.initials: LL
authors.lastname: Crussell-Porter
authors.forename: J P
authors.initials: JP
authors.lastname: Rindone
authors.forename: M A
authors.initials: MA
authors.lastname: Ford
authors.forename: D W
authors.initials: DW
authors.lastname: Jaskar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004357:Drug Synergism; D015725:Fluconazole / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011516:Prothrombin / Q000187:drug effects*; D011517:Prothrombin Time; D014859:Warfarin / Q000494:pharmacology*
chemical_list: D014859:Warfarin; D015725:Fluconazole; D011516:Prothrombin