Evaluation of pk/pd in the treatment with enrofloxacin in greater rheas, after multiple subcutaneous dosage.

DE LUCAS, JJ; SOLANO J.; RODRIGUEZ,C; DE VICENTE, M.; GONZALEZ, F.; MARTELLA, MB; LABAQUE, MC.; NAVARRO, JL

MADRID, ESPAÑA

Congreso; 3rd International Ratite Science Symposium; 2005

World´s Poultry Science Association

Intramuscular (i.m.) administration of enrofloxacin in ostriches at the currently recommended dosage regimen (5 mg/kbw twice daily for 2 days) is not adequate for clinical  efficacy (therapeutic levels were not reached) and produce muscular tissue damage (increased of CPK levels). On the other hand, the subcutaneous (s.c.) administration of this drug at a higher dose (15 mg/kbw twice daily for 3 days) was effective and did not cause tissue damage in ostriches. These facts indicate that s.c. administration is safer and effective than im. The pharmacokinetic behaviour (PK) of enrofloxacin after s.c. administration is unknown in rheas  and may have great clinical repercussions. The present work focuses on the PK of enrofloxacin (Baytrilâ 10% i.s.) and its active metabolite Ciprofloxacin (CIP), after multiple s.c. administration to six 5 month-old rheas of 15 mg/kbw twice daily for 5 days. Blood samples were taken at predefined times (0 to 12 hs after 1th administration; 0 and 1 hs after 2nd to 8th and 0 to 48 hs after 9th dose). Plasmatic levels of ENR and CIP were quantified using a HPLC/u.v technique. Slight accumulation and major permanence drug levels were observed after last dose (AUCdose-1=3.74 μg/h/ml; AUCdose-9=5.57μg/h/ml; MRTdose-1 =1.82μg/h/ml; MRTdose-9=2.86μg/h/ml). The effective use of the fluoroquinolones against clinically important animal pathogens is dependent on designing dosages that attain serum Cmax/MIC ratios of 10:1 and AUC0-24/MIC ratios of 125:1. Based on microbiological efficay indicators, this regimen showed efficacy only against the highly susceptible bacteria in rheas (MIC90<0.06 μg/ml) e.g. E. Coli, Salmonella spp or Pasterella spp. Future studies are necessary to find optimal dosage regimen for treatment of infections with Micoplasma spp. *This study was supported by a grant from the UCM (PR3/04-12470).