title: Adjusting the loading dose of magnesium sulfate for tocolysis.
abstract: The purpose of this prospective study was to establish a method to calculate a loading dose of magnesium sulfate so as to achieve therapeutic levels of tocolysis more quickly. Fifty patients in preterm labor were enrolled. In the first phase 25 patients were studied so that the apparent volume of distribution for the loading dose of magnesium sulfate could be estimated and an adjusted loading dose could be calculated. The efficacy of this adjusted loading dose was then tested on a further 25 patients in the second phase. We found that the apparent volume of distribution could be accurately estimated and an adjusted loading dose calculated, with the use of ideal body weight, degree of underweight, and current use of beta-sympathomimetics. In the adjusted loading dose group therapeutic levels were achieved more often, with higher postloading magnesium levels and a greater decrease in contraction index immediately after the loading dose. We conclude that an adjusted loading dose can be calculated for magnesium sulfate to optimize tocolytic therapy.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio 78284-7836.
authors.forename: J W
authors.initials: JW
authors.lastname: Wright
authors.forename: L E
authors.initials: LE
authors.lastname: Ridgway
authors.forename: R M
authors.initials: RM
authors.lastname: Patterson
mesh_terms: D000318:Adrenergic beta-Agonists / Q000627:therapeutic use; D001835:Body Weight; D005260:Female; D006801:Humans; D008278:Magnesium Sulfate / Q000008:administration & dosage* / Q000378:metabolism; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D011446:Prospective Studies; D012044:Regression Analysis; D015145:Tocolysis
chemical_list: D000318:Adrenergic beta-Agonists; D008278:Magnesium Sulfate