title: Geographic regional differences in rocuronium bromide dose-response relation and time course of action: an overlooked factor in determining recommended dosage.
abstract: BACKGROUND
  Geographic location is not acknowledged as a stratifying factor that can directly affect drug potency, because drugs are still licensed with the same recommended dose for different geographic regions. The aim of the current study was to compare the potency and duration of action of rocuronium bromide in 54 patients in three countries with different life habits, diet, and ambient conditions, namely white Austrians, white North Americans, and Han Chinese in China.
  
  
  METHODS
  Neuromuscular block of six consecutive 50-microg/kg rocuronium incremental doses followed by 300 microg/kg was evaluated using the Relaxometer mechanomyograph (Groningen University, Groningen, Holland). Dose-response curves were created using log-dose-probit transformation. The authors compared rocuronium bromide ED50, ED90, and ED95 (effective doses required for 50%, 90%, and 95% first twitch depression, respectively) as well as Dur25 and Dur0.8 (times from last incremental dose administration until 25% first twitch and 0.8 train-of-four ratio recovery, respectively) in patients of the three countries.
  
  
  RESULTS
  Rocuronium ED50, ED90, and ED95 were significantly higher in Austrian patients (258 +/- 68, 530 +/- 159, and 598 +/- 189 microg/kg) and Chinese patients (201 +/- 59, 413 +/- 107, and 475 +/- 155 microg/kg) compared with American patients (148 +/- 48, 316 +/- 116, and 362 +/- 149 microg/kg, respectively). Dur25 and Dur0.8 were significantly shorter in Austrian patients (22.3 +/- 5.5 and 36.9 +/- 12.8 min) and Chinese patients (30.4 +/- 7.5 and 45.7 +/- 15.9 min) compared with American patients (36.7 +/- 8.5 and 56.2 +/- 16.7 min, respectively).
  
  
  CONCLUSIONS
  The authors demonstrated a significant difference in rocuronium potency and duration of action among patients in the three countries. Larger studies are required for determining dosage recommendations for different geographic regions.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Graz Medical University, Austria. ashraf.dahaba@meduni-graz.at
authors.forename: Ashraf A
authors.initials: AA
authors.lastname: Dahaba
authors.forename: Seth I
authors.initials: SI
authors.lastname: Perelman
authors.forename: David M
authors.initials: DM
authors.lastname: Moskowitz
authors.forename: Henry L
authors.initials: HL
authors.lastname: Bennett
authors.forename: Aryeh
authors.initials: A
authors.lastname: Shander
authors.forename: Zhaoyang
authors.initials: Z
authors.lastname: Xiao
authors.forename: Lin
authors.initials: L
authors.lastname: Huang
authors.forename: Gang
authors.initials: G
authors.lastname: An
authors.forename: Helmar
authors.initials: H
authors.lastname: Bornemann
authors.forename: Georg
authors.initials: G
authors.lastname: Wilfinger
authors.forename: Barbara
authors.initials: B
authors.lastname: Hager
authors.forename: Peter H
authors.initials: PH
authors.lastname: Rehak
authors.forename: Werner F
authors.initials: WF
authors.lastname: List
authors.forename: Helfried
authors.initials: H
authors.lastname: Metzler
mesh_terms: D000328:Adult; D000732:Androstanols / Q000008:administration & dosage / Q000494:pharmacology*; D000768:Anesthesia, General; D044466:Asian People; D001317:Austria; D002681:China; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005260:Female; D005843:Geography; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage / Q000494:pharmacology*; D009656:North America; D011446:Prospective Studies; D000077123:Rocuronium; D044465:White People
chemical_list: D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium