Remifentanil has been used to suppress peri-extubation cough. Palonosetron, a 5-HT3 receptor antagonist, is an effective antiemetic, and 5-HT receptors mediate the cough reflex. We assessed the impact of palonosetron on effect-site concentration (Ce) of remifentanil for preventing emergence cough in females. Forty-five female patients undergoing laparoscopic cholecystectomy randomly received 0.075 mg of palonosetron (n = 21) or normal saline (n = 24) intravenously at the end of surgery. The remifentanil Ce for 50% (EC50) and for 95% (EC95) of patients were estimated via Dixon's up-and-down method or isotonic regression. Using Dixon's method, EC50 in the control group (1.33 ± 0.38 ng/mL) was comparable to that of the palonosetron group (1.42 ± 0.75 ng/mL) (p = 0.813). Using isotonic regression, EC50 (83% CIs) and EC95 (95% CIs) did not reveal significant differences between the control and the palonosetron groups (1.17 (0.86-1.43) and 1.90 (1.45-1.96) ng/mL and 0.88 (0.78-1.23) and 2.43 (1.94-2.47) ng/mL, respectively). No difference was found in the remifentanil Ce to suppress emergence cough in the palonosetron group compared with the control group. It may indicate no effect of palonosetron on antitussive activity of remifentanil.
Keywords: emergence cough; female; palonosetron; remifentanil.