Ephedrine accelerates psychomotor recovery from anesthesia in macaque monkeys

Background  Ephedrine is used in treatment of hypotension during anesthesia. We investigated its effects on the psychomotor recovery and its potential adverse reactions on cardiorespiratory functions in rhesus monkeys. Methods  The monkeys received 50 μg/kg medetomidine, 2.0 mg/kg S-ketamine with 150 IU hyaluronidase i.m. Pulse rate, blood pressure and saturation of haemoglobin were monitored for 20 minutes. Thereafter, 1 mg/kg of ephedrine or a placebo was administered i.m. and behavioural changes, pulse rate, blood pressure and saturation of haemoglobin were monitored every 5 minutes. Results  Ephedrine shortened recovery from anaesthesia from 80.4 ± 25.8 to 14.83 ± 13.70 minutes. Ephedrine also increased oxygen saturation of haemoglobin and systolic blood pressure and caused significant decrease in pulse rate 5 minutes after its administration. Conclusions  Ephedrine can be successfully used to accelerate psychomotor recovery after the use of common anesthetic protocols combining dissociative anesthetic agent and alpha 2-adrenoceptor agonist in primates.