title: Clinical pharmacology of mivacurium in pediatric patients less than off years old during nitrous oxide-halothane anesthesia.
abstract: We determined the dose-response relationship of mivacurium in infants 2-6 and 7-11 mo of age during nitrous oxide-halothane anesthesia. The neuromuscular and cardiovascular effects of a bolus dose of mivacurium larger than the ED95 in infants and young children from 2-23 mo of age were observed. The infusion rate of mivacurium required to maintain approximately 95% neuromuscular block was determined. There was no significant difference between the estimated dose-response relationship in infants 2-6 mo and that in infants 7-11 mo. The ED50 and ED95 were 44 micrograms/kg and 85 micrograms/kg for infants 2-11 mo (n = 70), r = 0.53. A bolus dose of 150 micrograms/kg mivacurium in infants (2-6 mo) produced 100% depression of the initial twitch height (T1) in 8 out of 9 infants and 85% depression in 1 infant. The time to onset of maximum block was 1.6 +/- 0.3 (0.7-2.7) (mean, SEM [range]) min, and time to recovery to 25% of T1 (T25) was 7.5 +/- 0.7 (5.5-11) min after 150 micrograms/kg in these patients. A bolus dose of 200 micrograms/kg mivacurium in infants and young children (7-23 mo) produced 100% depression of T1 in 14 of 17 patients, 97% depression in 2, and 90% depression in 1. The time to onset of maximum block was 1.5 +/- 0.1 (0.8-3) min and T25 was 10.3 +/- 1.5 (4.8-30.5) min after 200 micrograms/kg in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Anesthesiology, Children's Hospital of Pittsburgh, PA 15213-2583.
authors.forename: S K
authors.initials: SK
authors.lastname: Woelfel
authors.forename: B W
authors.initials: BW
authors.lastname: Brandom
authors.forename: F X
authors.initials: FX
authors.lastname: McGowan
authors.forename: D R
authors.initials: DR
authors.lastname: Cook
mesh_terms: D000769:Anesthesia, Inhalation; D002802:Cholinesterases / Q000097:blood; D004305:Dose-Response Relationship, Drug; D006221:Halothane; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D007223:Infant; D007262:Infusions, Intravenous; D007546:Isoquinolines / Q000008:administration & dosage / Q000494:pharmacology*; D000077590:Mivacurium; D009467:Neuromuscular Depolarizing Agents / Q000008:administration & dosage / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects; D009609:Nitrous Oxide
chemical_list: D007546:Isoquinolines; D009467:Neuromuscular Depolarizing Agents; D000077590:Mivacurium; D002802:Cholinesterases; D009609:Nitrous Oxide; D006221:Halothane