A literature study, to assess the potential use of Florfenicol in equine praxis was performed. It
was hypothetized that Florfenicol is a useful and safe antimicrobial for enteral and parenteral
treatment of horses suffering bacterial infections. Additionally an overview about available
Florfenicol preparations in Austria was given.
Material and Methods:
The search was carried out by different searching machines via internet and via the library at
the University of Veterinary Medicine in Vienna. Papers published after June 2013 were not
included. 14 studies were discovered, from which only one study has an veterinary trial. This
study describes the effects of Florfenicol in horses.
Just one article out of 14 tested Florfenicol (22mg/kg) in 6 horses. Plasma concentration is
higher after oral application than after i.m. application but falls faster after oral application.
Bioavailability was between 81% and 83% with a half-life of about 2-2.5 hours and an
distribution volume of 0,72 ± 0,17 l/kg . The excretion of the unchanged drug is under 13 %.
The total body clearance is 0,4 ± 0,1 /h/kg. All horses had loose feces in all application forms.
Sixteen veterinary preparations with Florfenicol were found. However the putative adverse
effects on gut flora and possible adverse effects of solvents and stabilizers need to be studied
further before any assessment can be given.
In the study from MCKELLAR and VARMA, 1996 no severe side-effects were found. However, what would happen when the drug is given for a longer period and/or in a larger
number of horses remains speculative. The currently available information is no objective
judgment on safety and efficacy.