Abstract

Alfaxalone is a neurosteroid, which produces dose-dependent GABAergic effects, ranging from sedation to general anesthesia. There are few reports describing the use of alfaxalone in wild mammals.¹ Our objective was to determine if alfaxalone would improve the induction and recovery characteristics of a medetomidine-azaperone combination without compromising cardiovascular stability. Six captive white-tailed deer were immobilized with medetomidine (0.15 mg/kg) plus azaperone (0.2 mg/kg) (MA). An additional six deer were immobilized using these drugs with the addition of 0.5 mg/kg of alfaxalone (MAA). Drugs were delivered IM (DD). Heart rate (HR), respiratory rate (RR), and rectal temperature (RT) were monitored every 5 minutes and compared with a two-way ANOVA for repeated measures. An arterial blood gas sample was obtained at 15 minutes post DD. Blood gas variables, induction and recovery times were compared with a paired t-test. One-hour post DD, atipamezole was administered at five times the medetomidine dose. There were no statistically significant differences between treatments in any cardiopulmonary parameters. HR and RT decreased significantly over time with both treatments. Both treatments induced hypoxemia (PaO₂ [MA, 54±7 {mean±SD} mm Hg; MAA, 55±10 mm Hg]) and hypoventilation (PaCO₂ [MA, 53.4±4 mm Hg; MAA, 53.4±4 mm Hg]). The addition of alfaxalone resulted in a statistically significant (p=0.0037) reduction in induction time (time to head down [MA, 11.1±3.8 min; MAA, 5.5±0.6 min]). Time to standing was significantly (p=0.049) longer with alfaxalone (standing [MA, 9.1±2 min; MAA, 12.2±2.6 min).

The addition of alfaxalone to medetomidine-azaperone significantly reduced induction time, while sparing cardiopulmonary function.

Literature Cited

1.  Bouts T, Karunaratna D, Berry K, et al. Evaluation of medetomidine-alfaxalone and medetomidine-ketamine in semi-free ranging Bennett’s wallabies (Macropus rufogriseus). J Zoo Wildl Med. 2011;42:617–622.