No regional difference in cisatracurium dose–response and time-course-of-action between patients in China and Bosnia

Abstract Background Variability in drug response could result from a variety of genetic and environmental factors that are often hard to define or quantify. A number of studies demonstrated regional geographic variations in potency of neuromuscular blocking agents (NMBAs). The aim of our study was to compare dose–response and time-course-of-action of cisatracurium besylate, an NMBA eliminated via the Hoffman degradation, in two countries with different life habits, diet, and ambient conditions; being Han Chinese in China and Caucasians in Bosnia. Methods Neuromuscular block of cisatracurium 20 µg kg −1 , followed by four incremental 10 µg kg −1 doses, and the remainder of 100 µg kg −1 was evaluated using the Relaxometer mechanomyograph (Groningen University, Groningen, The Netherlands). Dose–response curves were created using log-dose–probit-response transformation. Results There were no significant differences in cisatracurium mean (95% confidence intervals) ED 50 , ED 90 , and ED 95 (effective doses for 50%, 90%, and 95% first twitch depression) in Caucasian [39.1 (35.7–42.3), 50.6 (45.5–54.3), and 54.4 (49.8–58.9) µg kg −1 ] compared with Chinese patients [39.2 (35.1–43.1), 52.4 (47.9–56.8), and 56.9 (52.8–61.9) µg kg −1 ], respectively. There were no significant differences in mean (sd) Dur 25 and Dur 0.9 (time until 25% first twitch and 0.9 train-of-four ratio recoveries) in Caucasian [47.1 (6.4) and 77.5 (9.1) min)] compared with Chinese patients [(45.9 (4.7) and 72.3 (9.1) min)], respectively. Conclusions Cisatracurium dose–response relationship and time-course-of-action were not influenced by geographic location. Thus, cisatracurium would not require dose adjustments between patients living in the two geographic locations.