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- Ming Xiong, Zhao -Xin Zheng, Zu-Rong Hu, Jing He, Uchenna Madubuko, Dennis Grech, Xing-An Zhang, and Bo Xu.
- Department of Anesthesiology, General Hospital of Southern Theatre Command of PLA, 510010, Guangzhou, China.
- Anaesthesist. 2019 Jan 1; 68 (1): 15-21.
BackgroundThe pharmacodynamics of propofol are closely linked to gender. Dexmedetomidine can decrease propofol needs during propofol anesthesia. The aim of this study was to compare the gender differences on the calculated effect site median effective concentration (EC50) of propofol for loss of consciousness (LOC) after pretreatment with different concentrations of dexmedetomidine.MethodsIn this study 60 male and 60 female patients were randomly allocated to receive dexmedetomidine at target plasma concentrations of 0.0 ng/ml (0.0 group), 0.4 ng/ml (0.4 group), 0.6 ng/ml (0.6 group) and 0.8 ng/ml (0.8 group). Propofol was administered after dexmedetomidine had been intravenously infused for 15 min. The propofol infusion was targeted to provide an initial effect-site concentration of 1.0 μg/ml, followed by increments by 0.2 μg/ml when the effect-site concentration and target concentration of propofol were in equilibrium until LOC was established, where LOC was defined by the observer's assessment of alertness/sedation scale (OAA/S) score < 2.ResultsThe calculated effect-site EC50 of propofol LOC was higher in males than in females in the 0.0, 0.4, 0.6, and 0.8 groups (2.43 vs. 2.17, 1.99 vs. 1.82, 1.72 vs. 1.56 and 1.50 vs. 1.32 μg/ml, respectively, all p < 0.05). The hypnotic interaction between dexmedetomidine and propofol could be described with an additive model of pharmacodynamic interaction.ConclusionGender significantly influenced the calculated effect-site EC50 of propofol for LOC after pretreatment with different concentrations of intravenous dexmedetomidine. It was concluded that an additive interaction could describe the results seen. Thus, gender has to be considered when these drugs are co-administered.
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