Major Uses

Florfenicol is an antibiotic used mainly for the treatment of cattle, swine and fish with bovine respiratory disease (BRD). BRD is associated with Mannheimia haemolytic, Pasteurella multocida, Histophillus somni, and Mycoplasma bovis. Florfenicol prevents bacteria from growing when it binds to 50S ribosome in the animal.

Florfenicol is sometimes used in dogs and cats.

Common Precautions

Negative side effects associated with florfenicol include anorexia, decreased water consumption, or diarrhea. Instances of anaphylaxis and collapse have been reported in cattle. Trim loss may occur at some injection sires, or more severe reactions may occur if the injection is performed on a site other than the neck.

Gastrointestinal effects, including severe diarrhea, are potential problems in other species.

If an animal is intended to breed, florfenicol should not be used. The adverse reactions are unknown; however, the manufacturer states that this drug should not be used in cattle of breeding age or in swine intended for breeding.

Florfenicol should not be used in animals with a known allergy or hypersensitivity to the drug. If using IM route, cattle slaughter withdrawal is 28 days post injection.


The injection form of florfenicol should be stored between 2-30 degrees Celsius (36-86 degrees Fahrenheit). The drug should be used within 28 days of first use.

The oral form should be stored between 2-26 degrees Celsius (36-77 degrees Fahrenheit).


Florfenicol is available in oral and injectable forms. The recommended forms of medication vary depending on the species.

For the treatment of cattle with BRD, an injection dose of 20 mg/kg IM (in neck muscle only) should be used and repeated in 48 hours. A single 40 mg/kg SC dose (in neck) may also be used. The 20 mg/kg dose is equal to 3 mL of the injection per 100 lb. of body weight. 10 mL per injection site should not be exceeded. Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.