Incidence of ketamine-induced emesis in cynomologus monkeys (Macaca fascicularis) used for staphylococcal enterotoxin bioassay.

Ten (24%) of 41 cynomologus monkeys (Macaca fascicularis) showed emetic response to 2.5-20 mg/Kg of ketamine injected i.m. Reduction of the levels of ketamine to one half or less of the emetic level resulted in faster recovery from sedation yet provided adequate time for intubation and subsequent intragastric feeding of staphylococcal enterotoxin (SE) in only 6 of the 10 monkeys without emesis. The onset of the first emetic episode with ketamine was similar to that induced by staphylococcal enterotoxin A (SEA). Cynomologus monkeys showing emetic response to ketamine could still be used for SE bioassay if an experimentally determined non-emetic dose for individual monkeys is employed for sedation.