Pharmacokinetics and Pharmacodynamics of Intramuscular Administration of Alfaxalone in Peafowl (Pavo cristatus)
Abstract
Alfaxalone, a neuroactive steroid with anesthetic properties, is considered safe when used alone or in combination with other drugs for anesthesia,10 and its use has been studied in numerous species.2-9,11,12 The objective of this study is to assess the pharmacokinetics and pharmacodynamics of intramuscular alfaxalone in Indian peafowl (Pavo cristatus). Eight female peafowl from the Cheyenne Mountain Zoo were used. A control blood sample was obtained prior to administration of either 10 mg/kg (n=4) or 20 mg/kg (n=4) alfaxalone, 10 mg/ml solution (Alfaxan®). Blood was collected at 5, 10, 15, 30, and 60 min post injection, with monitoring of sedation score, heart rate, and respiratory rate at each timepoint. Peahens receiving a 10 mg/kg dose had smoother inductions and recoveries, though sedation level was generally scored as low, with no adverse reactions noted. All four birds in this group were considered fully recovered by the 60-min post-injection timepoint, although measurable alfaxalone plasma concentrations were present. All birds receiving 20 mg/kg experienced adverse effects, including seizure-like episodes and hypersensitivity to stimuli throughout the study. This dosing group experienced prolonged recoveries consistent with high plasma concentrations (>3000 ng/ml). Based on these findings, use of high doses of alfaxalone as the sole anesthetic agent is not recommended in this species; however, use in conjunction with other anesthetic/analgesic agents could be considered to allow for better sedation and smoother induction and recovery. Further research into combination inductions including alfaxalone and to assess pharmacokinetics and pharmacodynamics of alfaxalone in other avian species is needed.
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