Selected Antimicrobial Information – Companion Animal

Marbofloxacin [Companion]

Restriction Status



Species Usage Dose
Cats Label dose 2.75-5.5mg/kg PO q24h, for no longer than 30d
For hemoplasmosis
2.75mg/kg PO q24h for 14-28d (extra-label use)
Dogs Label dose 2.75-5.5mg/kg PO q24h, for no longer than 30d
For Pseudomonas otitis media/interna 5.5mg/kg PO q24h (extra-label use)

Brand Name(s)



Marbofloxacin 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 marbofloxacin is often not effective against Enterococcus spp. or Streptococcus spp., though it may be efficacious against Staphylococcus spp. It is also not effective against anaerobes. Distribution is wide, including into abscesses, and excretion is primarily as active drug in urine with a lesser component of biliary excretion. There is a post-antibiotic effect.

Acceptable Uses

  • Treatment of complicated or culture/susceptibility-confirmed resistant urinary tract infections or pyelonephritis.
  • Treatment of infected wounds or deep pyoderma associated with culture-confirmed susceptible organisms.
  • Treatment of otitis media associated with Pseudomonas aeruginosa.
  • Treatment of hemoplasmosis in cats.
  • As an alternative to enrofloxacin.

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

  • Zeniquin 25mg tablets
  • Zeniquin 50mg tablets
  • Zeniquin 100mg tablets
  • Zeniquin 200mg tablets


  • Adverse effects are comparable to enrofloxacin. Marbofloxacin should also 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.