Selected Antimicrobial Information – Companion Animal

Ciprofloxacin [Companion Animal]

Restriction Status



Species Usage Dose

For susceptible pathogens 5-15mg/kg PO q12h (extra-label use)

For susceptible pathogens 5-15mg/kg PO q12h (extra-label use)

Brand Name(s)



Ciprofloxacin is a bacteriocidal, concentration-dependent fluoroquinolone antibiotic with broad-spectrum activity against both gram-positive and gram-negative bacteria. It has good activity against Pseudomonas aeruginosa and Klebsiella spp., although resistance does occur in these bacteria. Gram-positive coverage is limited and often includes Staphylococcus spp., but ciprofloxacin is not effective against Enterococcus spp. and may not be effective against some Streptococcus spp. It is also not effective against anaerobes. This antimicrobial has poor bioavailability after oral dosing and is excreted in the urine and feces.

Acceptable Uses

  • For bacterial infections that are susceptible to enrofloxacin but use of enrofloxacin is cost-prohibitive and no other options exist.

Unacceptable Uses

  • Anaerobic infections, including empiric treatment of cat bite abscesses.
  • Treatment of Gram-positive infections without known susceptibility results.
  • Treatment of urinary tract infections or pyelonephritis where culture/susceptibility demonstrates susceptibility to lower tier antimicrobials.

Formulations Available within the OSU Pharmacy

  • Ciprofloxacin 250 mg tablets
  • Ciprofloxacin 750 mg tablets


  • The bioavailability of ciprofloxacin is poor in dogs after oral dosing (less than ½ that of enrofloxacin).
  • Ciprofloxacin is occasionally used as a cheaper alternative to enrofloxacin, but due to unpredictable absorption rates and the high likelihood of underdosing, this is recommended only as a last option.
  • Ciprofloxacin should not be used in in young, growing animal due to adverse effects on cartilage.
  • The dose of ciprofloxacin should be reduced in animals with severe renal failure.


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OSU VMC Antimicrobial Use Guidelines Copyright © 2018 by The Ohio State University College of Veterinary Medicine is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.