Comparison of three sedation protocols using midazolam and opioids in domestic ferrets (Mustela putorius furo)

Performing routine diagnostic tests in ferrets can be challenging without sedation, and intramuscular injections may be problematic due to their limited muscle mass. This study aimed to achieve moderate sedation levels using subcutaneously administered combinations of opioids and midazolam in ferrets. The effects, quality, and duration of sedation, as well as the cardiovascular and respiratory effects of midazolam in combination with three different opioids, were also evaluated. Twelve healthy adult ferrets were used in a randomized, blinded, crossover study. Three sedation protocols were evaluated: MM group with midazolam (0.5 mg/kg SC) and methadone (0.3 mg/kg SC), MB group with midazolam (0.5 mg/kg SC) and butorphanol (0.2 mg/kg SC) and MH group with midazolam (0.5 mg/kg SC) and hydromorphone (0.2 mg/kg SC). Sedation scores and vital parameters were recorded every five minutes. All 12 ferrets lost their righting reflex in the MB group and 11 out of 12 in the MH group. In the MM group, only 1 out of 12 lost his righting reflex, and for only 2 minutes. The median sedation duration (between loss and return of righting reflex) was 33.5 minutes (4–66) in the MH group and 42 minutes (36–72) in the MB group. MB group had a significantly shorter time to sternal recumbency, lateral recumbency and loss of righting reflex compared to MH group. The heart rate was significantly lower with MB when compared to MH, and MB induced significantly lower respiratory rates compared to both MH and MM. Retching and vomiting were observed in 84% of ferrets in the MH group, 42% in the MM group and 17% in the MB group. Subcutaneous administration of midazolam at 0.5 mg/kg in combination with either hydromorphone at 0.2 mg/kg or butorphanol at 0.2 mg/kg achieved moderate sedation. The combination of midazolam and butorphanol used in this study showed fewer side effects and variability in sedation duration, which may make it a more appropriate choice in a clinical setting.