Pharmacokinetics of Oral Flunixin Meglumine, Meloxicam, or Gabapentin in Three Black Rhinoceros ( Diceros Bicornis )

Abstract

Pharmacokinetics of single, separate doses of IV flunixin meglumine (1 mg/kg), IV meloxicam (0.5 mg/kg), oral flunixin meglumine (1 mg/kg), oral meloxicam (1 mg/kg), and oral gabapentin (15 mg/kg) in three adult black rhinoceroses (Diceros bicornis) were determined from serial blood collection made over 72 h. The concentration versus time profiles were analyzed for each drug and route in each individual rhinoceros, and individual pharmacokinetic parameters were calculated for each medication administered. Meloxicam had near complete bioavailability in each trial, while flunixin meglumine was generally lower. Oral meloxicam was noted with similar half-life values between all animals (range 9.22-14.52 h) tested, while oral gabapentin had a larger range (range 10.25-24.85 h). Oral flunixin meglumine achieved a lower Cmax (range 170.67-664.38 ng/ml) in this study compared with the mean Cmax (1,207 ng/ml) reported in a similar study in white rhinoceroses (Ceratotherium simum), but some overlap in range of values was noted. Oral flunixin meglumine Tmax (range 1.05-10.78 h) and halflife (range 3.88-14.85 h) values in black rhinoceroses was similar to mean values reported in white rhinoceroses (3 and 8.3 h, respectively).