Use of sugammadex to reverse alfaxalone anesthesia in rats

To test whether sugammadex, a reversal agent for steroid neuromuscular blocking drugs, could encapsulate the neurosteroid alfaxalone and accelerate anesthetic recovery.

Prospective, blinded, randomized, crossover study.

Thirty-six male and female adult Sprague-Dawley rats.

Six male and six female adult Sprague-Dawley rats were intravenously administered 3 mg kg^-1 alfaxalone followed 1 minute later by either 0.9% saline or 96 mg kg^-1 sugammadex, with a 1 week washout period between repeat anesthetics. A separate cohort of 12 rats was studied using an identical experimental design, but with a 6 mg kg^-1 alfaxalone dose. A third cohort of 12 rats was given 12 mg kg^-1 alfaxalone followed by saline or sugammadex (96 mg kg^-1 dose or 192 mg kg^-1 dose) using a Latin-square crossover design with 1 week between repeated anesthetics. Physiological and behavioral recovery responses were assessed every minute by an observer who was blinded to treatment. Data were analyzed using repeated-measures ANOVA with Šidák post hoc comparisons (p < 0.05).

Compared with saline controls, sugammadex shortened recovery times by 40-60% following anesthesia induction with the 3 or 6 mg kg^-1 alfaxalone doses (p ≤ 0.002). For the 12 mg kg^-1 alfaxalone dose, the low and the high sugammadex doses shortened recovery times by 25-50% and 50-61%, respectively, compared with saline controls, with all differences being significant (p ≤ 0.003) except for movement following tail clamp (p = 0.112-0.419). This higher sugammadex dose also shortened the same significant recovery end points compared with the lower sugammadex dose (p = 0.007-0.050). At higher alfaxalone doses, female rats exhibited significantly slower recoveries than male rats.

Sugammadex can be used to reverse anesthetic effects from alfaxalone in rats. Recovery speed from alfaxalone anesthesia is dependent on sugammadex dose and sex.