title: Pharmacokinetics of midazolam in Vietnamese subjects.
abstract: In order to examine the investigators' clinical suspicion that Vietnamese patients were more sensitive to the sedative effects of midazolam than were Caucasians, the pharmacokinetics of a single, weight-adjusted intravenous dose of midazolam (0.05 mg/kg) were compared in a group of healthy Caucasian and Vietnamese male volunteers. The Vietnamese group (n = 8) had a significantly lower height, lean body mass and mean weight (59.8 +/- 5.5 vs 72.1 +/- 8.1 kg, respectively) compared with the Caucasian group (n = 8). No significant differences were found between the Vietnamese and Caucasian groups with regard to distribution half-life of midazolam (8.38 +/- 13.1 vs 1.49 +/- 0.63 min, respectively), elimination half-life (2.49 +/- 1.80 vs 1.48 +/- 0.66 h, respectively), clearance (4.93 +/- 1.31 vs 5.90 +/- 2.12 mL/min per kg, respectively), steady state volume of distribution (0.863 +/- 0.497 vs 0.530 +/- 0.132 L/kg, respectively) or percentage of unbound drug in plasma (4.89 +/- 0.74 vs 4.11 +/- 1.08, respectively). This suggests that dosage of midazolam in Vietnamese should be based on total bodyweight. Two Vietnamese subjects who were brothers had marked elevation of distribution half-life and initial volume of distribution and lesser elevations in elimination half-life and volume of distribution at steady state. This suggests that the known subgroup of subjects who demonstrate dyshomogeneity in midazolam volume of distribution may be genetically determined.
authors.affiliation: University of Melbourne Department of Medicine, Western Hospital, Victoria, Australia.
authors.forename: K R
authors.initials: KR
authors.lastname: Balson
authors.forename: D J
authors.initials: DJ
authors.lastname: Morgan
authors.forename: B H
authors.initials: BH
authors.lastname: Richmond
authors.forename: M E
authors.initials: ME
authors.lastname: McAlindon
authors.forename: S L
authors.initials: SL
authors.lastname: Elliott
authors.forename: N D
authors.initials: ND
authors.lastname: Yeomans
mesh_terms: D000293:Adolescent; D000328:Adult; D014151:Anti-Anxiety Agents / Q000493:pharmacokinetics*; D044466:Asian People; D001824:Body Constitution; D006207:Half-Life; D006801:Humans; D006993:Hypnotics and Sedatives / Q000493:pharmacokinetics*; D008297:Male; D008874:Midazolam / Q000493:pharmacokinetics*; D008875:Middle Aged; D014744:Vietnam; D044465:White People
chemical_list: D014151:Anti-Anxiety Agents; D006993:Hypnotics and Sedatives; D008874:Midazolam