Adverse reaction reporting of interaction between warfarin and fluoroquinolones

Arch Intern Med. 1991 May;151(5):1003-4.

Abstract

Reports to the Food and Drug Administration's Adverse Drug Reaction Reporting System of prolonged prothrombin time due to a suspected interaction between warfarin sodium and a fluoroquinolone were reviewed. Five reports of patients who experienced this adverse reaction 2 to 16 days after the addition of a fluoroquinolone to their treatment regimen are described. Possible mechanisms of action that are discussed include inhibition of warfarin metabolism by the anti-infective agent and displacement of warfarin's binding to protein. Physicians need to be aware of this interaction and closely monitor prothrombin time in patients concurrently receiving warfarin and a fluoroquinolone.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Ciprofloxacin / adverse effects*
  • Drug Interactions
  • Female
  • Humans
  • Male
  • Middle Aged
  • Norfloxacin / adverse effects*
  • Product Surveillance, Postmarketing
  • United States
  • United States Food and Drug Administration
  • Warfarin / adverse effects*

Substances

  • Ciprofloxacin
  • Warfarin
  • Norfloxacin