OBJECTIVETo evaluate the impact of gender differences on the dose-effect relationship of cisatracurium.

METHODSEighty ASA class I or II patients (40 male and 40 female patients) undergoing elective abdominal surgeries received a single-dose intravenous injection of midazolam and fentanyl. The male and female patients were subdivided into 4 equal groups to receive a intravenous bolus of 20, 30, 40, or 50 µg/kg of cisatracurium. The neuromuscular block was measured using a neuromuscular transmission monitor, and the responses were defined in terms of the percentages of maximum suppression in T1 of TOF of the adductor pollicis muscle. According to log-probit transformation of the data of the dose and response, the dose-response curve of cisatracurium was established through linear regression. The onset time of vecuronium was also observed.

RESULTSThe ED95 value of cisatracurium in male patients was 67.4±4.4 µg/kg, significantly higher than that in female patients (48.7±1.0 µg/kg, P<0.05). No significant variation in the onset time was found in the 4 dose groups of either male or female patients (P>0.05).

CONCLUSIONFemale patients are more sensitive to cisatracurium than male patients.