Potential warfarin-ciprofloxacin interaction in patients receiving long-term anticoagulation.
This study prospectively evaluated the potential interaction between the oral anticoagulant warfarin and the quinolone antimicrobial agent ciprofloxacin. After a 10-day placebo lead-in phase, 16 patients stabilized with long-term warfarin therapy were randomized to receive ciprofloxacin 500 mg or a matching placebo twice/day for 10 days. International normalized ratios (INRs) measured by both standard laboratory analysis and by Coumatrak (finger-stick) methods were evaluated at 3- to 5-day intervals. No patient experienced a significant increase in INR. No patient experienced a bleeding event. These data support the fact that a warfarin-ciprofloxacin interaction does not routinely occur at this dosage and duration of ciprofloxacin therapy.
Bianco
T M
TM
Department of Pharmacology, University of Texas Health Science Center, San Antonio.
Bussey
H I
HI
Farnett
L E
LE
Linn
W D
WD
Roush
M K
MK
Wong
Y W
YW
D000328:Adult; D000368:Aged; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D004311:Double-Blind Method; D004347:Drug Interactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011517:Prothrombin Time; D013997:Time Factors; D014859:Warfarin / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use
D002939:Ciprofloxacin; D014859:Warfarin