Evaluation of a medetomidine-midazolam combination for immobilizing and sedating Japanese monkeys (Macaca fuscata)

We clinically and clinicopathologically investigated the immobilizing and sedative effects of a medetomidine-midazolam (MM) combination in Japanese monkeys (Macaca fuscata) and its antagonism with atipamezole. MM (medetomidine, 60 microg/kg; midazolam, 0.3 mg/kg) was administered intramuscularly to each monkey (n = 11). All animals were laterally recumbent within 13 +/-6 min after administration of MM. This combination induced deep sedation accompanied by analgesia, muscle relaxation, and markedly depressed arousal reactions to external stimuli. After administration of atipamezole (240 microg/kg intramuscularly), the animals recovered rapidly and smoothly to their normal postures within 10 +/-2 min. In this study, the hematologic and serum biochemical parameters of Japanese monkeys given MM did not differ significantly from those of Japanese monkeys under general anesthesia via ketamine. Salivary a-amylase activities (stress indexes) ranged from 4 to 99 kU/l in Japanese monkeys, similar to levels measured in humans. An important advantage of MM was that its effects were reversible with atipamezole. We have confirmed that MM is valuable as a chemical restraint agent in Japanese monkeys for various experimental procedures.