Selected Antimicrobial Information – Companion Animal

Enrofloxacin [Companion]

Restriction Status



Species Usage Dose
Cats Label dose 2.5mg/kg PO, IV or SQ q12h or 5mg/kg PO, IV, or SQ q24h for no more than 30d (ideally, 7-14d)
Dogs Label dose 5-10mg/kg PO, IV or SQ q24h for no more than 30d (high end of dose range preferred for Pseudomonas soft tissue infections)
For skin or genitourinary infections 5-10mg/kg PO q24h for 7-14d (for pyoderma, to resolution of clinical signs or one week past resolution)
For deep pyoderma, lower respiratory tract infections, or complicated UTIs 5-20mg/kg PO, IV, or IM q24h for 7-14d (for pyoderma, to resolution of clinical signs or one week past resolution)
For sepsis or orthopedic infection
10-20mg/kg PO, IV, IM, or SQ q24h
For enteric infections 5mg/kg PO q12h; treatment may need to continue for up to 8wks in cases of granulomatous colitis
For Otitis media (Pseudomonas) 20mg/kg q24h

Brand Name(s)



Enrofloxacin is a bactericidal, concentration-dependent fluoroquinolone antibiotic with activity primarily against Gram-negative aerobes, such as Enterobacteriaceae and Pseudomonas aeruginosa. Gram-positive coverage is limited and often includes Staphylococcus spp., but enrofloxacin is not effective against Enterococcus spp. and may not be effective against some Streptococcus spp. It is also not effective against anaerobes. Distribution is wide; enrofloxacin crosses the blood-brain barrier and can enter abscesses, the prostate, and bone. Excretion is primarily in bile, with a component of active drug in urine.

Acceptable Uses

  • Treatment of complicated or culture/susceptibility-confirmed resistant urinary tract infections, pyelonephritis, and prostatitis.
  • Treatment of infected wounds or deep pyoderma associated with culture-confirmed susceptible organisms, or empiric treatment of suspected Pseudomonas aeruginosa (e.g. groomer-associated deep pyoderma). Also useful for treatment of otitis media/interna.
  • Treatment of respiratory tract infections, including pneumonia.
  • Treatment of osteomyelitis or septic arthritis, with or without the addition of rifampin.
  • Treatment of enteric infections associated with Gram-negative organisms such as E. coli (granulomatous colitis) or Campylobacter spp.
  • Superficial pyoderma based on C/S.

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

  • Enrofloxacin 100mg/ml injectable suspension
  • Enrofloxacin 20mg/ml oral suspension
  • Enrofloxacin 22.7mg tablet
  • Enrofloxacin 68mg tablet
  • Enrofloxacin 136mg tablet
  • Baytril 22.7mg/ml injectable suspension
  • Baytril 100mg/ml injectable suspension
  • Baytril 22.7mg tablet
  • Baytril 68mg tablet


  • Enrofloxacin is metabolized in vivo to its active form, ciprofloxacin. Ciprofloxacin, however, is less readily absorbed across the gastrointestinal tract in veterinary species when compared to enrofloxacin. PK/PD studies suggest that GI absorption of ciprofloxacin in dogs ranges from approximately 30-80%. Ciprofloxacin (Cipro®) is occasionally used as a cheaper alternative to enrofloxacin, but due to unpredictable absorption rates and the high likelihood of underdosing, this is not recommended.
  • Retinal degeneration is a possible adverse side effect in cats, and enrofloxacin use is not recommended in this species where other antimicrobial choices are available. 5mg/kg/day is the maximum daily dose that should be given to cats.
  • Enrofloxacin should not be used in young, growing animal due to adverse effects on cartilage.


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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.