title: Magnesium sulphate for prevention of eclampsia: are intramuscular and intravenous regimens equivalent? A population pharmacokinetic study.
abstract: OBJECTIVE
  To compare magnesium sulphate concentrations achieved by intramuscular and intravenous regimens used for the prevention of eclampsia.
  
  
  METHODS
  Low-resource obstetric hospitals in Nagpur and Vellore, India.
  
  
  METHODS
  Pregnant women at risk for eclampsia due to hypertensive disease.
  
  
  METHODS
  A pharmacokinetic study was performed as part of a randomised trial that enrolled 300 women comparing intramuscular and intravenous maintenance regimens of magnesium dosing. Data from 258 enrolled women were analysed in the pharmacokinetic study. A single sample was drawn per woman with the expectation of using samples in a pooled data analysis.
  
  
  METHODS
  Pharmacokinetic parameters of magnesium distribution and clearance.
  
  
  RESULTS
  Magnesium clearance was estimated to be 48.1 dl/hour, volume of distribution to be 156 dl and intramuscular bioavailability to be 86.2%. The intramuscular regimen produced higher initial serum concentrations, consistent with a substantially larger loading dose. At steady state, magnesium concentrations in the intramuscular and intravenous groups were comparable. With either regimen, a substantial number of women would be expected to have serum concentrations lower than those generally held to be therapeutic.
  
  
  CONCLUSIONS
  Clinical implications were that a larger loading dose for the intravenous regimen should be considered; where feasible, individualised dosing of magnesium sulphate would reduce the variability in serum concentrations and might result in more women with clinically effective magnesium concentrations; and lower dose magnesium sulphate regimens should be considered with caution.
authors.affiliation: Department of Bioengineering, University of Washington, Seattle, WA, USA.
authors.forename: D H
authors.initials: DH
authors.lastname: Salinger
authors.forename: S
authors.initials: S
authors.lastname: Mundle
authors.forename: A
authors.initials: A
authors.lastname: Regi
authors.forename: H
authors.initials: H
authors.lastname: Bracken
authors.forename: B
authors.initials: B
authors.lastname: Winikoff
authors.forename: P
authors.initials: P
authors.lastname: Vicini
authors.forename: T
authors.initials: T
authors.lastname: Easterling
mesh_terms: D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001682:Biological Availability; D004334:Drug Administration Schedule; D004461:Eclampsia / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007273:Injections, Intramuscular; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000627:therapeutic use; D008657:Metabolic Clearance Rate; D011225:Pre-Eclampsia / Q000188:drug therapy*; D011247:Pregnancy; D055815:Young Adult
chemical_list: D000927:Anticonvulsants; D008278:Magnesium Sulfate