Abstract

The objective of this study was to assess the sedation and reversal quality, and cardiorespiratory effects, of subcutaneous midazolam and flumazenil, respectively, in healthy corn snakes (Pantherophis guttatus) and Mexican black kingsnakes (Lampropeltis californiae nigrita). In a randomized, double-blinded, crossover study, Mexican black king snakes (n = 7) and corn snakes (n = 12) were administered subcutaneous midazolam 2 mg/kg or volume equivalent of 0.9% NaCl with sedation variables (spontaneous movement, menace gesture response, frequency of tongue flicking, and righting reflex) assessed after 60 minutes. Subcutaneous flumazenil 0.05 mg/kg was then administered to all animals at 60 minutes and sedation variables were reassessed after one, four, and 24 hours to assess for complete reversal effects and evidence of re-sedation. The data demonstrated subjectively moderate sedation effects one hour following subcutaneous midazolam in both corn snakes and Mexican black kingsnakes, which was characterized by reduction in spontaneous movement, tongue flicking, and menace gesture response. A righting reflex was maintained in all snakes but delayed compared to baseline and saline administration. Subsequent subcutaneous flumazenil administration (0.05 mg/kg) resulted in appropriate antagonistic sedation effects within one hour in corn snakes and within 24 hours in Mexican black kingsnakes. No evidence of re-sedation was observed within 24 hours post-reversal administration in both species. No adverse cardiorespiratory effects were observed with midazolam or flumazenil administration in either snake species. Midazolam produced safe, appropriate moderate sedation effects in apparently healthy Mexican black kingsnakes and corn snakes and can be considered for noninvasive procedures and handling. Flumazenil effectively reversed the sedative effects of midazolam with no evidence of re-sedation by 24 hours post administration.