Review
Magnesium sulfate in eclampsia and pre-eclampsia: pharmacokinetic principles
J F Lu et al. Clin Pharmacokinet. 2000 Apr.
Abstract
Magnesium sulfate (MgSO4) is the agent most commonly used for treatment of eclampsia and prophylaxis of eclampsia in patients with severe pre-eclampsia. It is usually given by either the intramuscular or intravenous routes. The intramuscular regimen is most commonly a 4 g intravenous loading dose, immediately followed by 10 g intramuscularly and then by 5 g intramuscularly every 4 hours in alternating buttocks. The intravenous regimen is given as a 4 g dose, followed by a maintenance infusion of 1 to 2 g/h by controlled infusion pump. After administration, about 40% of plasma magnesium is protein bound. The unbound magnesium ion diffuses into the extravascular-extracellular space, into bone, and across the placenta and fetal membranes and into the fetus and amniotic fluid. In pregnant women, apparent volumes of distribution usually reach constant values between the third and fourth hours after administration, and range from 0.250 to 0.442 L/kg. Magnesium is almost exclusively excreted in the urine, with 90% of the dose excreted during the first 24 hours after an intravenous infusion of MgSO4. The pharmacokinetic profile of MgSO4 after intravenous administration can be described by a 2-compartment model with a rapid distribution (a) phase, followed by a relative slow beta phase of elimination. The clinical effect and toxicity of MgSO4 can be linked to its concentration in plasma. A concentration of 1.8 to 3.0 mmol/L has been suggested for treatment of eclamptic convulsions. The actual magnesium dose and concentration needed for prophylaxis has never been estimated. Maternal toxicity is rare when MgSO4 is carefully administered and monitored. The first warning of impending toxicity in the mother is loss of the patellar reflex at plasma concentrations between 3.5 and 5 mmol/L. Respiratory paralysis occurs at 5 to 6.5 mmol/L. Cardiac conduction is altered at greater than 7.5 mmol/L, and cardiac arrest can be expected when concentrations of magnesium exceed 12.5 mmol/L. Careful attention to the monitoring guidelines can prevent toxicity. Deep tendon reflexes, respiratory rate, urine output and serum concentrations are the most commonly followed variables. In this review, we will outline the currently available knowledge of the pharmacokinetics of MgSO4 and its clinical usage for women with pre-eclampsia and eclampsia.
Similar articles
-
Magnesium sulphate therapy in women with pre-eclampsia and eclampsia in Kuwait.
Omu AE, Al-Harmi J, Vedi HL, Mlechkova L, Sayed AF, Al-Ragum NS. Omu AE, et al. Med Princ Pract. 2008;17(3):227-32. doi: 10.1159/000117797. Epub 2008 Apr 10. Med Princ Pract. 2008. PMID: 18408392
[Magnesium sulfate in obstetrics: current data].
Azria E, Tsatsaris V, Goffinet F, Kayem G, Mignon A, Cabrol D. Azria E, et al. J Gynecol Obstet Biol Reprod (Paris). 2004 Oct;33(6 Pt 1):510-7. doi: 10.1016/s0368-2315(04)96564-7. J Gynecol Obstet Biol Reprod (Paris). 2004. PMID: 15567967 Review. French.
Clinical pharmacokinetic properties of magnesium sulphate in women with pre-eclampsia and eclampsia.
Okusanya BO, Oladapo OT, Long Q, Lumbiganon P, Carroli G, Qureshi Z, Duley L, Souza JP, Gülmezoglu AM. Okusanya BO, et al. BJOG. 2016 Feb;123(3):356-66. doi: 10.1111/1471-0528.13753. Epub 2015 Nov 24. BJOG. 2016. PMID: 26599617 Free PMC article. Review.
[MgSO4-therapy in pre-eclampsia/eclampsia. Review of the literature].
Minkov R, Aleksandrov K. Minkov R, et al. Akush Ginekol (Sofiia). 2003;42 Suppl 2:24-7. Akush Ginekol (Sofiia). 2003. PMID: 14619751 Review. Bulgarian. No abstract available.
Maternal-fetal effects of magnesium sulfate on serum osmolality in pre-eclampsia.
van der Heyden JJ, Standley CA. van der Heyden JJ, et al. J Matern Fetal Neonatal Med. 2002 Apr;11(4):270-4. doi: 10.1080/jmf.11.4.270.274. J Matern Fetal Neonatal Med. 2002. PMID: 12375684
Cited by
Exogenous Melatonin Directly and Indirectly Influences Sheep Oocytes.
Chen Y, Shan X, Jiang H, Guo Z. Chen Y, et al. Front Vet Sci. 2022 May 26;9:903195. doi: 10.3389/fvets.2022.903195. eCollection 2022. Front Vet Sci. 2022. PMID: 35720845 Free PMC article.
Effect of Mg-Gluconate on the Osmotic Fragility of Red Blood Cells, Lipid Peroxidation, and Ca2+-ATPase (PMCA) Activity of Placental Homogenates and Red Blood Cell Ghosts From Salt-Loaded Pregnant Rats.
Rojas D, Abad C, Piñero S, Medina Y, Chiarello DI, Proverbio F, Marín R. Rojas D, et al. Front Physiol. 2022 Jan 27;13:794572. doi: 10.3389/fphys.2022.794572. eCollection 2022. Front Physiol. 2022. PMID: 35153828 Free PMC article.
Case Series: Video-Assisted Minimally Invasive Cardiac Surgery During Pregnancy.
Lu A, Ye Y, Hu J, Wei N, Wei J, Lin B, Wang S. Lu A, et al. Front Med (Lausanne). 2021 Dec 22;8:781690. doi: 10.3389/fmed.2021.781690. eCollection 2021. Front Med (Lausanne). 2021. PMID: 35004748 Free PMC article.
Efficacy of Magnesium Sulfate on Maternal Mortality in Eclampsia.
Padda J, Khalid K, Colaco LB, Padda S, Boddeti NL, Khan AS, Cooper AC, Jean-Charles G. Padda J, et al. Cureus. 2021 Aug 20;13(8):e17322. doi: 10.7759/cureus.17322. eCollection 2021 Aug. Cureus. 2021. PMID: 34567870 Free PMC article. Review.
Magnesium sulphate for treating acute bronchiolitis in children up to two years of age.
Chandelia S, Kumar D, Chadha N, Jaiswal N. Chandelia S, et al. Cochrane Database Syst Rev. 2020 Dec 14;12(12):CD012965. doi: 10.1002/14651858.CD012965.pub2. Cochrane Database Syst Rev. 2020. PMID: 33316083 Free PMC article.
References
- J Clin Invest. 1958 Oct;37(10):1362-72 - PubMed
- Annu Rev Pharmacol Toxicol. 1981;21:165-204 - PubMed
- Obstet Gynecol. 1988 Jan;71(1):122-37 - PubMed
- Am J Obstet Gynecol. 1990 May;162(5):1141-5 - PubMed
- Obstet Gynecol Clin North Am. 1988 Jun;15(2):355-77 - PubMed
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
- Ovid Technologies, Inc.
- Springer
Other Literature Sources
- The Lens - Patent Citations
Medical
- ClinicalTrials.gov
- Genetic Alliance