Effects of ketamine hydrochloride on serum biochemical and hematologic variables in rhesus monkeys (Macaca mulatta)

Serum biochemical and hematologic values were obtained from Rhesus monkeys (Macaca mulatta) before and 15 minutes after intramuscular injection with ketamine hydrochloride (5-10 mg/kg). A 345% increase in serum creatine kinase activity 15 minutes after ketamine administration was attributed to muscle damage caused by the injection. Decreases in erythrocyte count, hemoglobin, hematocrit, total leukocyte count, lymphocyte count, and the serum concentrations of glucose, total protein, albumin, and other serum analytes were all attributed to the reversal (by ketamine) of the excitement or "alarm reaction" associated with physical restraint. The decrease in circulating erythrocytes and lymphocytes indicated a redistribution of these cells from the circulating blood to the spleen and extravascular sites, respectively. Decreases in concentrations of total protein, albumin, and several other serum analytes suggested an influx of fluid into the vascular space. The decrease in glucose may also reflect the reversal of an epinephrine-induced hyperglycemia in the excited awake monkey. These alterations should be considered when designing studies and interpreting data for Rhesus monkeys.