Pharmacokinetics of oxytetracycline in clinical cases in the red-necked wallaby (Macropus rufogriseus)

Oxytetracycline, administered at 40 mg kg-1 by intravenous injection, was used as part of the treatment of three female red-necked wallabies, Macropus rufogriseus, with suspected Fusobacterium necrophorum infections. The plasma concentrations of this drug in blood samples collected at intervals up to 24 hours after administration were measured using a biological assay. The pattern of decline in plasma oxytetracycline concentration with time was consistent with a two-compartment model. The half-life of the elimination phase was calculated to be 11.4 hours and the apparent volume of distribution was found to be 2.041 litres kg-1. These results provide a basis for devising appropriate oxytetracycline dosage regimes for the species.