FLORFENICOL
Chemistry/Storage, Stability, Compatibility
A fluorinated analog of thiamphenicol, florfenicol is commercially available as light yellow to straw-colored injectable solution also containing nethyl-2-pyrolidone, propylene glycol and polyethylene glycol. It should be stored between 2°-30°C (36°-86°F).Pharmacology - FLORFENICOL
Like chloramphenicol, florfenicol is a broad spectrum antibiotic that has activity against many bacteria. It acts by binding to the 50S ribosome, thereby inhibiting bacterial protein synthesis.Uses, Indications - The drug is approved for use in cat le only (in the USA) for the treatment of bovine respiratory disease (BRD) associated with Pasteurella haemolytica, Pasteurella multocida and Haemophilus somnus.
Because florfenicol has activity against a wide range of microorganisms (e.g., Mycoplasma), it may be useful for treating other infections in cat le (or other species) as well, but specific data supporting these uses is presently lacking.
Pharmacokinetics - FLORFENICOL
After IM injection, approximately 79% of the dose is bioavailable. The drugappears to be well distributed throughout the body, including achievement of therapeutic levels inthe CSF. In cat le, only about 13% is bound to serum proteins. Mean serum half life is 18 hours, but wide interpatient variation exists.Contraindications, Precautions, Reproductive Safety
No contraindications are listed in thepackage insert, but see residue warnings (below). Safety or effects when used in breeding cattle, during pregnancy or during lactation are unknown and the manufacturer states that the drug is notfor use in cattle of breeding age.Caution: Do not give this drug IV.
Adverse Effects, Warnings
Noted transient adverse reactions in cattle include anorexia, decreased water consumption or diarrhea. Injection site reactions can occur that may result in trim loss. Reactions may be more severe if injected at sites other than the neck.Overdosage - In toxicology studies where feeder calves were injected with up to 10X of the recommended dosage, the adverse effects noted above were seen, plus increased serum enzymes werenoted. These effects were generally transient in nature. Long term (43 day) standard dosage studiesshowed a transient decrease in feed consumption, but no long-term negative effects were noted.