Midazolam as an effective intravenous adjuvant to prolonged ketamine sedation in young rhesus (Macaca mulatta) and Vervet (Cercopithecus aethiops sabaeus) monkeys: A preliminary report

The present study investigated a recently developed benzodiazepine, midazolam, as an intravenous adjuvant to ketamine in infant monkeys undergoing prolonged sedation during positron emission tomography of the brain and heart. Subjects were two rhesus macaque (Macaca mulatta) and ten vervet monkeys (Cercopithecus aethiops sabaeus) ranging in age from 26 to 260 days. Midazolam was an effective intravenous adjuvant to ketamine. This treatment regime resulted in complete immobilization of the animals. Ketamine infusion rates did not vary significantly with age for either species. Sensitivity to midazolam appeared to be age‐dependent in vervets because significantly lower dose rates were sufficient to maintain anesthesia in older animals. For rhesus monkeys, midazolam dose rates decreased until approximately 4 months of age, and increased gradually thereafter. © 1993 Wiley‐Liss, Inc.