Pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin and their interaction with diclofenac sodium in cows

Abstract

The pharmacokinetics of enrofloxacin was studied in 5 cows following single dose of intramuscular administration (5 mg.kg-') alone and along wi th dic10fenac sodium (250 mg, total dose). Therapeutic concentration (0.1 ,ug.mL-') was maintained in plasma up to 12 and 24 hforenrotloxacin alone and enrofloxacin along with dic10fenac sodium respectively. Following concurrent administration of enrofloxacin along with diclofenac sodium, the tv. K (9.2 h), T (2 h), MRT (13.2 h) and Cl (1.4 L.kg-') were significantly higher compared to those following enroflo;acin given";ione (t l12 Ke5.9 h, T -0.4 h, MRT-6.8 h, CI-0.82 L.kg-I h-I ). However, when enrofloxacin was administered along with dicIofenac sodium,mi'l;e AVC (3.8 ,ug.h.mL-I) and Cmax (0.2 ,ug.mL-I) were significantly lower, compared to when enrofloxacin was given along (AUC-6 ,ug.hmL-1 and Cmux-1.5 ,ug.mL-'). The plasma concentration of ciprofloxacin (metabolite of enrotloxacin) was significantly lower following administration of enrofloxacin along with diclofenac sodium compared to enrofloxacin administered alone. Our results indicate that co-administration of diclofenac sodium with enrofloxacin could lead to drug interaction Le. altering the pharmacodynamic and pharmacokinetics of enrofloxacin.