Pharmacokinetics of meloxicam in adult goats and its analgesic effect in disbudded kids

Abstract

The pharmacokinetics and analgesic effect of the nonsteroidal anti-inflammatory drug meloxicam (0.5 mg/kg) in goats were investigated. In a randomized, cross-over design the pharmacokinetic parameters were investigated in adult goats (n = 8) after single intravenous and oral administration. The analgesic effect was evaluated in kids using a randomized, placebo controlled and blinded protocol. Kids received meloxicam (n = 6) once daily and their siblings (n = 5) got isotonic NaCl intramuscularly while still anaesthetized after cautery disbudding and injections were repeated on three consecutive days. In the adult goats after intravenous administration the terminal half-life was 10.9 ± 1.7 h, steady-state volume of distribution was 0.245 ± 0.06 L/kg, and total body clearance was 17.9 ± 4.3 mL/h/kg. After oral administration bioavailability was 79 ± 19%, C(max) was 736 ± 184 ng/mL, T(max) was 15 ±5 h, although the terminal half-life was similar to the intravenous value, 11.8 ± 1.7 h. Signs of pain using a visual analogue scale were smaller in kids treated with meloxicam compared with kids treated with placebo on the first day after disbudding, but subsequently no difference in pain was noticeable. Plasma cortisol and glucose concentrations did not differ between the two groups.