Selected Antimicrobial Information – Companion Animal

Chloramphenicol [Companion]

Restriction Status



Species Usage Dose
Cats For oral use 12.5-20mg/kg q12h for 7-14d (treatment should not exceed 14d) (extra-label use)
For parenteral use 12-30mg/kg q12h IV (extra-label use)
Dogs For oral use 45-60mg/kg q8h for 7d-14d (treatment should not exceed 14d) (extra-label use)
For parenteral use 45-60mg/kg q6-8h IV (extra-label use)

Brand Name(s)

Viceton®, Chloromycetin®


Chloramphenicol is a bacteriostatic, time-dependent acetamide antibiotic with a very broad spectrum of activity, including Gram-positive and Gram-negative aerobes, and anaerobes. It is not effective against Pseudomonas aeruginosa. Plasmid-mediated resistance to chloramphenicol develops in Gram-negative bacteria (e.g. Enterobacter cloacae, Klebsiella spp.) over time. Chloramphenicol is widely distributed throughout the body, crosses the blood-brain barrier, and penetrates necrotic tissues and abscesses. Elimination is through hepatic metabolism, and inactive metabolites are excreted in urine.

Acceptable Uses

  • Treatment of conditions in which broad-spectrum coverage is required (pneumonia, peritonitis, internal abscesses, cellulitis, etc.). Culture/susceptibility are indicated prior to initiating therapy.
  • Treatment of rickettsial infections.
  • Pyoderma in dogs.

Unacceptable Uses

  • Should not be used in animals with pre-existing leukopenia or anemia.

Formulations Available within the OSU Pharmacy

  • Chloramphenicol 1g tablet
  • Chloramphenicol 250mg tablet


  • Idiosyncratic, irreversible aplastic anemia is a rare complication of human exposure to chloramphenicol, which can lead to death. Gloves should always be worn when handling chloramphenicol.
  • Reversible bone marrow suppression has also been noted in cats and dogs. Reversible bone marrow suppression is very common in cats, especially with treatment >14 days. It is rare in dogs.
  • Reversible peripheral neuropathy/hindlimb paresis of unknown etiology occurs in up to 30% of dogs treated with chloramphenicol.
  • Chloramphenicol can decrease the clearance of other hepatically-metabolized drugs (e.g. barbituates).
  • GI side effects (i.e. vomiting and anorexia) are common in dogs and cats treated with chloramphenicol.
  • When given orally, chloramphenicol should be administered with food to improve its absorption.
  • It is very difficult to find injectable formulations of chloramphenicol.


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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.