Objective: To evaluate the efficacy and safety of hydromorphone administered SC in four-toed hedgehogs (Atelerix albiventris).
Animals: 12 healthy adult hedgehogs.
Methods: Hedgehogs underwent 2 randomized, blinded, placebo-controlled, complete crossover studies. Hind limb withdrawal latencies in response to an acute thermal noxious stimulus were measured to evaluate the antinociceptive efficacy of hydromorphone. Baseline latencies were obtained prior to injection and collected again at 0.5, 1, 2, 4, and 6 hours following injection. Based on pilot studies, single doses of SC hydromorphone at 0.15 and 0.3 mg/kg were evaluated for efficacy in crossover trials. Safety of single (0.15 and 0.3 mg/kg) and multiple doses of hydromorphone (0.3 mg/kg, SC, q 4 h, for 3 doses) was also assessed. In addition to monitoring behavior during latency measurements, animals were evaluated for overt sedation and daily changes in food intake, body weight, and running wheel activity for 6 days after injection to evaluate for adverse effects.
Results: Hydromorphone at 0.15 mg/kg provided antinociception lasting < 4 hours, and 0.3 mg/kg provided antinociception lasting < 6 hours. Hydromorphone produced transient abnormal behaviors at both doses, including vocalization, chewing motions of the jaw, and paw raising. There were no statistically significant differences in body weight or running wheel activity between treatments for single or multiple doses of hydromorphone. Three doses of 0.3 mg/kg hydromorphone (q 4 h) produced a statistically significant decrease (median, -9.7%; range, -64% to 10%) in 6-day total food intake.
Clinical relevance: Subcutaneous hydromorphone (0.15 to 0.3 mg/kg) can be used for short-term antinociception with transient adverse effects in hedgehogs.
Keywords: analgesia; antinociception; dysphoria; hedgehog; hydromorphone.