Subcutaneous alfaxalone for sedation of the domestic ferret (Mustela putorius furo)

Background

Veterinary care of the domestic ferret often utilizes chemical restraint for venipuncture, radiographs, and ultrasonography. Common forms of chemical restraint for ferrets include inhalant anesthetics and parenteral sedatives. Disadvantages of these forms of chemical restraint include adverse patient reaction and environmental contamination for inhalant anesthetics while small muscle mass and patient reactivity are challenging for intramuscular injections. Alfaxalone is a unique neurosteroid anesthetic that can be used as an induction agent intravenously and a sedative agent intramuscularly and subcutaneously. Subcutaneous injection appears to be well tolerated in small exotic species due to the increased volume the subcutaneous space can accommodate as well as the ease of administration.

Methods

A randomized, blinded, complete crossover study evaluating two doses (10 mg/kg and 12.5 mg/kg) of subcutaneous (SC) alfaxalone alone was performed in 10 clinically healthy ferrets (5 neutered males and 5 spayed females). Once alfaxalone was administered sedation scores (body posture, righting reflex, jaw tone, front limb withdrawal, and toe pinch) and vital parameters (heart rate, respiratory rate, rectal temperature, SpO₂ and blood pressure) were evaluated at regular intervals.

Results

Sedation characterized by the loss of righting reflex for more than ten minutes was observed in 90% of ferrets in both groups. The higher dose of alfaxalone (12.5 mg/kg) produced a statistically significant increase in the duration of sedation, as well as in the values of all sedation scores. Temperature significantly decreased over time for both groups, while SpO₂ and respiratory rate did not display any significant changes. At both doses, no cardiovascular depression was noted but there were significant increases in heart rate and blood pressure parameters.

Conclusion

Subcutaneous alfaxalone in ferrets produces adequate sedation characterized by the loss of righting reflex and easy limb manipulation with no significant adverse effects. This type of sedation is appropriate for noninvasive procedures such as a physical exam, ultrasonography, and radiographic positioning without manual restraint. The limitations for SC alfaxalone, as a sole sedative agent, include the variable range in times to onset and variable durations of sedation.