Antinociceptive effects of nalbuphine hydrochloride in Hispaniolan Amazon parrots (Amazona ventralis)

Objective-To evaluate the antinociceptive effects and duration of action of nalbuphine HCl administered IM on thermal thresholds in Hispaniolan Amazon parrots (Amazona ventralis). Animals-14 healthy adult Hispaniolan Amazon parrots of unknown sex. Procedures-3 doses of nalbuphine (12.5, 25, and 50 mg/kg, IM) and saline (0.9% NaCl) solution (control treatment) were evaluated in a blinded complete crossover experimental design by use of foot withdrawal threshold to a noxious thermal stimulus. Baseline data on thermal threshold were generated 1 hour before administration of nalbuphine or saline solution; thermal threshold measurements were obtained 0.5, 1.5, 3, and 6 hours after administration. Results-Nalbuphine administered IM at 12.5 mg/kg significantly increased the thermal threshold (mean change, 2.4 degrees C), compared with results for the control treatment, and significantly changed thermal threshold for up to 3 hours, compared with baseline results (mean change, 2.6 to 3.8 degrees C). Higher doses of nalbuphine did not significantly change thermal thresholds, compared with results for the control treatment, but had a significant effect, compared with baseline results, for up to 3 and 1.5 hours after administration, respectively. Conclusions and Clinical Relevance-Nalbuphine administered IM at 12.5 mg/kg significantly increased the foot withdrawal threshold to a thermal noxious stimulus in Hispaniolan Amazon parrots. Higher doses of nalbuphine did not result in significantly increased thermal thresholds or a longer duration of action and would be expected to result in less analgesic effect than lower doses. Further studies are needed to fully evaluate the analgesic effects of nalbuphine in psittacine species. (Am J Vet Res 2011;72:736-740)