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Chloramphenicol for Veterinary Use

For Veterinary Practices
Prescribe Now
For Pet & Horse Owners
Manage Your Prescriptions

by Barbara Forney, VMD


Therapeutic Class

Dogs, cats and horses

May Be Prescribed by Vets for:
Susceptible bacterial infections

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Basic Information

Chloramphenicol is a broad-spectrum bacteriostatic antibiotic that is effective against a wide variety of bacteria, including gram-positive, gram-negative, and anaerobic bacteria. The oral form of Chloramphenicol palmitate is well absorbed and is widely distributed throughout the body. It reaches high drug-concentrations in most tissues, including difficult-to-penetrate areas such as synovial fluid, the central nervous system, and the eyes. It is metabolized and eliminated primarily by the liver.

A major drawback to Chloramphenicol is the occurrence of a rare but very serious health risk for humans who handle this drug. See precautions.

Dogs and Cats

Chloramphenicol is used in wide variety of infections in dogs and cats, including meningitis, chronic bronchitis, prostatitis, pyoderma, otitis media and interna, Rickettsia, Mycoplasma, Nocardia, and Chlamydia.

Chloramphenicol has a longer half-life in cats than in other species. Cats receiving a high dose of Chloramphenicol for more than two weeks may need additional monitoring. Cats are also more susceptible to drug interactions between Chloramphenicol and other drugs that are metabolized by the liver.


Chloramphenicol is used to treat bacterial infections due to susceptible organisms. It is sometimes used in the treatment of Salmonellosis, and Lawsonia and is frequently used in cases where long term antibiotics are necessary such as pleuropneumonia, peritonitis and abdominal abscesses.

Side Effects

Chloramphenicol may cause dose related, reversible, bone marrow suppression in animals. It should be avoided or used with caution in animals with a pre-existing blood disorders. Loss of appetite is the most-common side effect. Other side effects include vomiting, diarrhea, and depression.


PRECAUTION FOR HUMANS: Rare cases of aplastic anemia may occur in some individuals who are exposed to this drug. For these people, even skin contact can cause permanent damage to the bone marrow. Because this anemia is not reversible, Chloramphenicol should only be used when other suitable antibiotics are not available, and should be used with extreme caution. Gloves and masks should be worn when handling this drug. This drug should be used in a well-ventilated location. Chloramphenicol should not be handled by children or pregnant women.

Chloramphenicol is metabolized in the liver. It should be used with care in patients with liver or kidney disease. Dose adjustment or monitoring of antibiotic blood level may be necessary.

Chloramphenicol should be avoided or used with caution in neonates. Kittens in particular may have difficulty metabolizing this drug. Chloramphenicol may be used in older animals with normal kidney and liver function.

Chloramphenicol crosses the placenta and is present in milk. There are reports of fetal bone-marrow suppression, and teratogenic effects. It is not recommended for use during pregnancy or lactation.

It is illegal to use Chloramphenicol in animals that may enter the food chain.

Drug Interactions

Chloramphenicol is not compatible with some antibiotics. It should not be used with bactericidal antibiotics such as Penicillin, Cephalosporins and Aminoglycosides.

Chloramphenicol can slow the metabolism of barbiturate anesthetics.

Chloramphenicol may interact with: Lidocaine, Cimetidine, myelosuppressive drugs, Phenobarbital, Primidone, Propofol or Rifampin.


A Chloramphenicol overdose could cause significant bone-marrow toxicity. If recognized promptly, oral overdose should be treated with gastric-emptying protocols.

About the Author

Dr. Barbara Forney

Dr. Barbara Forney is a veterinary practitioner in Chester County, Pennsylvania. She has a master's degree in animal science from the University of Delaware and graduated from the University of Pennsylvania School of Veterinary Medicine in 1982.

She began to develop her interest in client education and medical writing in 1997. Recent publications include portions of The Pill Book Guide to Medication for Your Dog and Cat, and most recently Understanding Equine Medications published by the Bloodhorse.

Dr. Forney is an FEI veterinarian and an active member of the AAEP, AVMA, and AMWA.