Monday September 21, 1998 - Question 10

A 48 year-old female is being evaluated in the emergency department for spontaneous gingival bleeding.  She is on warfarin for chronic DVT prophylaxis.  The patient had been stabilized on warfarin (2.5 mg daily), which maintained her INR just above 2.  Her INR is 3.9 today.  The patient reports that she recently completed a 7-day course of ciprofloxacin, a fluoroquinolone antibiotic, for a lower urinary tract infection.

Which of the following statements concerning the above case is true?

A. Interactions between quinolones and warfarin are highly predictable.
B. All quinolone antibiotics are likely to interact with warfarin.
C. INR monitoring is not necessary when these agents are used together.
D. Ciprofloxacin is a CYP-450 enzyme inducer.
E. Interactions with quinolone antibiotics and warfarin may be delayed.
 
 

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