Comparison of the Efficacy and Cardiorespiratory Effects of Medetomidine-Based Anesthetic Protocols in Ring-Tailed Lemurs (Lemur Catta)

Abstract

The relative efficacies and cardiorespiratory effects of three injectable anesthetic combinations containing medetomidine were evaluated in ring-tailed lemurs (Lemur catta). In addition, the direct effects of medetomidine on heart rate and blood pressure were evaluated in lemurs anesthetized with isoflurane. For injectable anesthesia, captive adult ring-tailed lemurs were anesthetized with medetomidine and ketamine (0.04-0.06 mg/kg, i.m. and 3 mg/kg, i.m., respectively), medetomidine, butorphanol, and ketamine (0.04 mg/kg, i.m., 0.4 mg/kg, i.m., and 3 mg/kg, i.m., respectively), or medetomidine, butorphanol, and midazolam (0.04 mg/kg, i.m., 0.4 mg/kg, i.m., and 0.3 mg/kg, i.m., respectively). For inhalation anesthesia, lemurs were mask-induced and maintained with isoflurane for 30 min before receiving medetomidine (0.04 mg/kg, i.m.). Sedation produced by medetomidine-ketamine was unpredictable and of short duration. Both medetomidine-butorphanol-ketamine (MBK) and medetomidine-butorphanol-midazolam (MBMz) provided adequate anesthesia for routine physical exams; however, the effects of MBMz lasted longer than those of MBK. Heart rates and respiratory rates were within clinically normal ranges for all groups, and lemurs remained normotensive throughout the study. Common side effects such as hypertension and bradycardia associated with the use of alpha2-adrenergic receptor agonist combinations in other species were not observed. Likewise, medetomidine administration had no effect on HR in lemurs receiving isoflurane. Lemurs in all groups were well ventilated and remained well oxygenated throughout the procedures, though arterial partial pressure of O2 was lowest in the MBMz group. All three injectable medetomidine combinations were effective in ring-tailed lemurs but only MBK and MBMz provided adequate depth and duration of anesthesia for use as sole regimes. For many clinical procedures in lemurs, MBMz offers advantages over MBK because of its longer duration of action and its rapid and more complete reversibility with specific antagonists.

Anesthetic Effect of a Combination of Medetomidine-Midazolam-Butorphanol in Cynomolgus Monkeys (<i>Macaca fascicularis</i>)

“…However, monkeys present special hazards to handlers, such as biting and zoonotic infection, and often must be anesthetized for use in a study. Balanced anesthesia consisting of a combination of medetomidine, midazolam and butorphanol (Me-Mi-Bu) has been successfully used in mice (ICR, BALB/c and C57BL/6J) [10, 12], beagle dogs [8, 18], other species of monkeys ( Erythrocebus patas and Lemur catta ) [9, 20] and African lions ( Panthera leo ) [19]. Here, we investigated the use of the Me-Mi-Bu combination in cynomolgus monkeys ( Macaca fascicularis ) and evaluated the antagonistic effect of atipamezole on anesthesia induced by the Me-Mi-Bu combination.…”

“…administration was made in the hind limb (the quadriceps muscle) of each animal. Dose 3 of the Me-Mi-Bu combination was determined by references to Kalema-Zikusoka et al [9] and Williams et al [20]. The i.m.…”

“…The Me-Mi-Bu combination induces cardiorespiratory effects, such as bradycardia, hypotension and respiratory depression, in two strains of monkeys [9, 20]. In addition, the authors noted that cynomolgus monkeys developed bradycardia, hypotension, respiratory depression (as determined by auscultation) and loss of thermoregulatory ability by injection of the Me-Mi-Bu combination (data not shown).…”

The common marmoset in biomedical research: experimental disease models and veterinary management

“…The preferred combination of MMB is medetomidine 0.04 mg/kg, midazolam 0.4 mg/kg, and butorphanol 0.4 mg/kg delivered via intramuscular injection (IM). This combination was optimized for marmosets based on doses reported in ring-tailed lemurs [ 52 ] and patas monkeys [ 53 ]. The administration of atipamezole 0.2 mg/kg IM at the end of surgery reverses the effect of medetomidine and facilitates smooth recovery from anesthesia.…”