Pharmacokinetics, tolerance and serum thromboxane inhibition of carprofen in the dog

Abstract

Abstract The non‐steroidal anti‐inflammatory drug (NSAID) carprofen was administered to dogs as a mixed‐micelle solution at a dose rate of 0–7 mg/kg intravenously, as a palatable paste at a dose rate of 0–7 mg/kg orally, and as an oral tablet formulation at a dose rate of 0–7 mg/kg and 4‐0 mg/kg orally for pharmacokinetic studies. It was also administered as an oral tablet formulation at a dose rate of 9‐0 mg/kg orally daily for 14 days in a tolerance study. The pharmacokinetics following intravenous administration at a dose rate of 0–7 mg/kg indicate that carprofen has a small volume of distribution (Vd area = 0–09‐0‐25 litres), a slow systemic clearance (Cls = 1–34‐5‐57 ml/min) and an elimination half‐life of 3–20‐11‐77 hours. Both oral paste and tablet preparations were highly bioavailable and absorption was proportional to dose rate at 0–7 mg/kg and 4‐0 mg/kg bodyweight. Given once daily at dose rates likely to be used clinically it is unlikely to accumulate in the plasma. Carprofen administered as a palatable paste at a dose rate of 0–7 mg/kg did not inhibit serum thromboxane generation and this drug may therefore have a mode of action different from most NSAIDs. Carprofen was well tolerated when administered as an oral tablet formulation at a dose rate of 9.0 mg/kg daily for 14 days in healthy beagle dogs.