Effects of early atipamezole reversal of medetomidine-ketamine anesthesia in mice.

Rodents are often anesthetized by using ketamine and medetomidine, with reversal by atipamezole. Methods vary for times of administration of the atipamezole, and literature is lacking regarding appropriate reversal time. We investigated the recovery of mice reversed with atipamezole 10 min (early) or 40 min (late) after induction of anesthesia. Time to regain pinch-reflex or righting reflex did not differ between the 2 reversal points, but time to walking was significantly greater in mice that underwent early reversal with atipamezole. This delay was not mitigated by administration of atropine as part of the anesthetic regimen. Inclusion of acetylpromazine in the anesthetic regimen shortened the time needed to reach a surgical plane of anesthesia but also prolonged recovery times as determined by righting reflex and time to walking.