Pharmacokinetics of ceftazidime after intravenous and intramuscular administration to domestic cats.
The pharmacokinetic properties of ceftazidime, a third generation cephalosporin, were investigated in five cats after single intravenous (IV) and intramuscular (IM) administration at a dose rate of 30 mg/kg. Minimum inhibitory concentrations (MICs) of ceftazidime for some Gram-negative (Escherichia coli, n=11) and Gram-positive (Staphylococcus spp., n=10) strains isolated from clinical cases were determined. An efficacy predictor, measured as the time over which the active drug exceeds the bacteria minimum inhibitory concentration (T>MIC), was calculated. Serum ceftazidime disposition was best fitted by a bi-compartmental and a mono-compartmental open model with first-order elimination after IV and IM dosing, respectively. After IV administration, distribution was rapid (t(1/2(d)) 0.04+/-0.03 h), with an area under the ceftazidime serum concentration:time curve (AUC((0-infinity))) of 173.14+/-48.69 microg h/mL and a volume of distribution (V((d(ss)))) of 0.18+/-0.04 L/kg. Furthermore, elimination was rapid with a plasma clearance of 0.19+/-0.08 L/hkg and a t(1/2) of 0.77+/-0.06 h. Peak serum concentration (C(max)), T(max), AUC((0-infinity)) and bioavailability for the IM administration were 89.42+/-12.15 microg/mL, 0.48+/-0.49 h, 192.68+/-65.28 microg h/mL and 82.47+/-14.37%, respectively. Ceftazidime MIC for E. coli ranged from 0.0625 to 32 microg/mL and for Staphylococcus spp. from 1 to 64 microg/mL. T>MIC was in the range 35-52% (IV) and 48-72% (IM) of the recommended dosing interval (8-12h) for bacteria with a MIC(90)4 microg/mL.
Albarellos
G A
GA
Cátedra de Farmacología, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Chorroarín 280 (1427), Buenos Aires, Argentina. albarell@fvet.uba.ar
Ambros
L A
LA
Landoni
M F
MF
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D002415:Cats / Q000378:metabolism*; D002442:Ceftazidime / Q000008:administration & dosage / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D005260:Female; D007273:Injections, Intramuscular / Q000662:veterinary; D007275:Injections, Intravenous / Q000662:veterinary; D008297:Male
D000900:Anti-Bacterial Agents; D002442:Ceftazidime