The pharmacokinetics of phenylbutazone and its interaction with dexamethasone in chicks

Abstract

The present study aims to investigate the influence of dexamethasone administration on the pharmacokinetics of phenylbutazone and its plasma concentration as well as its pharmacological interaction in a chick model. The analgesic median effective doses (ED50s) of phenylbutazone and dexamethasone are separately evaluated as 5.60 and 0.63 mg/kg, IP, and their ED50s are estimated and reduced to 1.76 and 0.19 mg/kg, IP, respectively. The type of pharmacological interaction between phenylbutazone and dexamethasone is synergistic as determined by the isobolographic analysis. The phenylbutazone administration at 11.20 mg/kg, IP has plasma concentrations of 39.