PHARMACOKINETICS AND TOLERANCE OF FLORFENICOL IN EQUIDAE

Florfenicol was administered to horses and ponies at a dose rate of 22 mg/kg bwt by i.v., i.m. and oral routes. Following i.v. administratio n it had an elimination half-life of 1.8 +/- 0.9 h, a body clearance o f 0.4 +/- 0.1 l/h.kg and a volume of distribution at steady-state of 0 .7 +/- 0.2 l/kg. It was highly bioavailable following i.m. (81%) and o ral (83%) administration. Less than 15% of the administered dose was e xcreted unchanged in the urine during the 30 h following administratio n. Animals treated with florfenicol had elevated bilirubin concentrati ons. Florfenicol was well tolerated by animals in the present study al though all animals had loose faeces following administration by each r oute. At present, florfenicol cannot be recommended for clinical use u ntil multiple dose studies have been carried out to confirm its safety .