Pharmacodynamics and chiral pharmacokinetics of carprofen in calves

The non-steroidal anti-inflammatory drug, carprofen, was administered intravenously as the racemate at a dose rate of 0.7 mg kg-1 to six Friesian bull calves aged 8-10 weeks. Anti-inflammatory properties were indicated by attenuation of temperature rise at sites of intradermal injection of the irritants, carrageenin and dextran, but responses were not statistically significant at most recording times. Carrageenin- and dextran-induced swelling were not significantly reduced by carprofen. Carprofen reduced ex vivo serum thromboxane B2 synthesis but this effect was also not significant at most sampling times. Enantioselective pharmacokinetics of carprofen was demonstrated, plasma concentrations of the R(-) enantiomer predominating at all sampling times. It is concluded that inhibition of cyclo-oxygenase is unlikely to be the sole mechanism of action of carprofen in calves.