Pharmacokinetic interaction of isopropylaminophenazone and phenylbutazone in the horse

Publisher Website
Google Scholar
Abstract
The pharmacokinetics of the two active anti‐inflammatory compounds, isopropylaminophenazone and phenylbutazone, were investigated in the horse. Therapeutic intravenous doses of 12 mg/kg body weight and 6 mg/kg body weight, respectively, were given separately and as a combination to five horses. Blood concentrations were described by two‐compartment kinetics. Significantly lower total clearances, unchanged volumes of distribution, and hence significantly higher elimination half‐lives were found for both substances when administered as a combination. It is possible that the hydroxylated metabolites of the substances are responsible for the presumed metabolic interference.