Medical uses of magnesium sulfate

From Wikipedia, the free encyclopedia

Magnesium sulfate
Magnesium sulfate heptahydrate
Clinical data
Trade namesEpsom salt, others
Routes of
IV, IM, by mouth, topical
ATC code
CAS Number
PubChem CID
Chemical and physical data
FormulaMgSO4 – 7H2O
Molar mass120.366
3D model (JSmol)
  • [O-]S(=O)(=O)[O-].[Mg+2]
  • InChI=1S/Mg.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2

Magnesium sulfate as a medication is used to treat and prevent low blood magnesium and seizures in women with eclampsia.[1] It is also used in the treatment of torsades de pointes, severe asthma exacerbations, constipation, and barium poisoning.[1][2] It is given by injection into a vein or muscle as well as by mouth.[1][2] As epsom salts, it is also used for mineral baths.[3]

Common side effects include low blood pressure, skin flushing, and low blood calcium.[1] Other side effects may include vomiting, muscle weakness, and decreased breathing.[4] While there is evidence that use during pregnancy may harm the baby, the benefits in certain conditions are greater than the risks.[5] Its use during breastfeeding is deemed to be safe.[5] The way it works is not fully understood, but is believed to involve depressing the action of neurons.[1]

Magnesium sulfate came into medical use at least as early as 1618.[6] It is on the World Health Organization's List of Essential Medicines.[7][8] In 2021, magnesium salts were the 211th most commonly prescribed medication, with more than 2 million prescriptions.[9][10]


Magnesium sulfate is available as magnesium sulfate dihydrate,[11] magnesium sulfate heptahydrate,[2][12] and magnesium sulfate monohydrate.[13]


The World Health Organization recommends magnesium sulfate heptahydrate for medical injection.[14]

External uses[edit]

Bath salts[edit]

Magnesium sulfate is used in bath salts, especially for foot baths to soothe sore feet. The reason for the inclusion of the salt is partially cosmetic: the increase in ionic strength prevents some of the temporary skin wrinkling (partial maceration) which would occur with plain water baths.

Epsom salt baths have been claimed to also soothe and hasten recovery of muscle pain, soreness, or injury. However, these claims have not been scientifically confirmed.[15] The solubility of magnesium sulfate water is inhibited by lipids in lotions resulting in variable absorption rates when applied to the skin. Temperature and concentration are also factors.[16]


Research on topical magnesium (for example epsom salt baths) is limited.[17]

Isolation tanks[edit]

Magnesium sulfate is commonly used in flotation therapy to prepare the concentrated solutions that fill the isolation tanks. Its high solubility in water yields baths with high specific gravity that make the body more buoyant. Its negligible toxicity is an important asset in that application.

Mineral waters[edit]

Magnesium and sulfate ions are naturally present in some mineral waters.[18]

Drawing paste[edit]

In the United Kingdom, a medication containing magnesium sulfate, called "drawing paste", is claimed to be useful for small boils or localised infections,[19] and removing splinters.[20] The standard British Pharmacopoeia composition is dried magnesium sulfate 47.76% (by mass), phenol 0.49%, and glycerol to balance.[19]

Internal uses[edit]

Magnesium sulfate intravenous solution

Magnesium sulfate can be administered internally by oral, respiratory, intravenous, or intrathecal routes.

Magnesium deficiency[edit]

Injected magnesium sulfate is used as a replacement therapy for magnesium deficiency.[21]

Orally administered magnesium sulfate is laxative and thus the magnesium is not well absorbed.


Magnesium sulfate may be used as an antiarrhythmic agent for torsades de pointes in cardiac arrest under the ECC guidelines and for managing quinidine-induced arrhythmias.[22]


Magnesium sulfate may be used as bronchodilator after beta-agonist and anticholinergic agents have been tried, e.g. in severe exacerbations of asthma,[23] The salt can be administered by nebulization[23] or by intravenous injection.


Magnesium sulfate is effective in decreasing the risk that pre-eclampsia progresses to eclampsia.[24] Intravenous magnesium sulfate is used to prevent and treat seizures of eclampsia. It reduces the systolic blood pressure but does not alter the diastolic blood pressure, so the blood perfusion to the fetus is not compromised. It is also commonly used for eclampsia where compared to diazepam or phenytoin it results in better outcomes.[25][26]

Early delivery[edit]

Magnesium sulfate was once used as a tocolytic,[27][28] but meta-analyses have failed to support it as an anti-contraction medication.[29][30] Usage for prolonged periods (more than five to seven days) may result in health problems for the baby.[31]

In those at risk of an early delivery, magnesium sulfate appears to decrease the risk of cerebral palsy.[32][33] It is unclear if it helps those who are born at term.[34] Guidelines for the use of magnesium sulfate in mothers at risk of preterm labour are not strongly adhered to.[35]

Barium chloride poisoning[edit]

Magnesium sulfate is used to treat barium chloride poisoning,[36] where sulfate binds to barium to form insoluble barium sulfate.

Lead poisoning[edit]

Magnesium sulfate was historically used as a treatment for lead poisoning. Prior to the development of chelation therapy, cases of accidental lead ingestion were often immediately treated with magnesium sulfate, which would cause the lead to be precipitated out and, with a high enough dose, literally purged from the digestive system as insoluble lead(II) sulfate.[37][38] In this application, magnesium sulfate saw particular use in veterinary medicine of the early-to-mid 20th century; Epsom salt was already available on many farms for agricultural purposes, and it was often prescribed in the treatment of farm animals which inadvertently ingested lead.[39][40]

Adjuvant to local anesthetics[edit]

Magnesium sulfate can be administered intrathecally with opioids to prolong their analgesic duration.[41]


Magnesium sulfate has been used as an experimental treatment of Irukandji syndrome caused by envenomation by certain species of Irukandji jellyfish, but the efficacy of this treatment remains unproven.[42]


An abnormally elevated plasma concentration of magnesium is called hypermagnesemia.

See also[edit]


  1. ^ a b c d e "Magnesium Sulfate". The American Society of Health-System Pharmacists. Archived from the original on 21 May 2016. Retrieved 8 January 2017.
  2. ^ a b c British national formulary : BNF 69 (69 ed.). British Medical Association. 2015. p. 696. ISBN 9780857111562.
  3. ^ Kogel JE, Trivedi NC, Barker JM, Krukowski ST (2006). "Magnesium Minerals and Compounds". Industrial Minerals & Rocks: Commodities, Markets, and Uses. SME. p. 625. ISBN 9780873352338. Archived from the original on 18 September 2017.
  4. ^ World Health Organization (2009). Stuart MC, Kouimtzi M, Hill SR (eds.). WHO Model Formulary 2008. World Health Organization. p. 75. hdl:10665/44053. ISBN 9789241547659.
  5. ^ a b "Magnesium sulfate Use During Pregnancy". Archived from the original on 2 July 2017.
  6. ^ Willett E (2006). Magnesium. The Rosen Publishing Group. p. 5. ISBN 9781404210073. Archived from the original on 18 September 2017.
  7. ^ World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
  8. ^ World Health Organization (2021). World Health Organization model list of essential medicines: 22nd list (2021). Geneva: World Health Organization. hdl:10665/345533. WHO/MHP/HPS/EML/2021.02.
  9. ^ "The Top 300 of 2021". ClinCalc. Archived from the original on 15 January 2024. Retrieved 14 January 2024.
  10. ^ "Magnesium Salts - Drug Usage Statistics". ClinCalc. Retrieved 14 January 2024.
  11. ^ "Magnesium sulfate dihydrate". DrugBank Online. Retrieved 27 March 2022.
  12. ^ "Magnesium sulfate heptahydrate". DrugBank Online. Retrieved 27 March 2022.
  13. ^ "Magnesium sulfate monohydrate". DrugBank Online. Retrieved 27 March 2022.
  15. ^ Ingraham P. "Does Epsom Salt Work? The science of Epsom salt bathing for recovery from muscle pain, soreness, or injury". Pain Science. Archived from the original on 10 September 2016. Retrieved 29 August 2016.
  16. ^ "Does Epsom Salt Work?". Retrieved 5 May 2018.
  17. ^ Rath L. "Why Take an Epsom Salts Bath?". WebMD.
  18. ^ "Bath – Hot Springs". Archived from the original on 27 October 2007. Retrieved 16 October 2016.
  19. ^ a b "Boots Magnesium Sulfate Paste B.P. – Patient Information Leaflet (PIL) – (eMC)". Retrieved 14 April 2018.
  20. ^ Ryan. "Removing a splinter with Magnesium Sulphate". TipKing.
  21. ^ "Pharmaceutical Information – Magnesium Sulfate". RxMed. Archived from the original on 3 April 2009. Retrieved 6 July 2009.
  22. ^ "CPR and First Aid: Antiarrhythmic Drugs During and Immediately After Cardiac Arrest (section)". American Heart Association. Retrieved 29 August 2016. Previous ACLS guidelines addressed the use of magnesium in cardiac arrest with polymorphic ventricular tachycardia (ie, torsades de pointes) or suspected hypomagnesemia, and this has not been reevaluated in the 2015 Guidelines Update. These previous guidelines recommended defibrillation for termination of polymorphic VT (ie, torsades de pointes), followed by consideration of intravenous magnesium sulfate when secondary to a long QT interval.
  23. ^ a b Blitz M, Blitz S, Hughes R, Diner B, Beasley R, Knopp J, Rowe BH (July 2005). "Aerosolized magnesium sulfate for acute asthma: a systematic review". Chest. 128 (1): 337–344. doi:10.1378/chest.128.1.337. PMID 16002955..
  24. ^ Duley L, Gülmezoglu AM, Henderson-Smart DJ, Chou D (November 2010). "Magnesium sulphate and other anticonvulsants for women with pre-eclampsia". The Cochrane Database of Systematic Reviews. 2010 (11): CD000025. doi:10.1002/14651858.CD000025.pub2. PMC 7061250. PMID 21069663.
  25. ^ Duley L, Henderson-Smart DJ, Walker GJ, Chou D (December 2010). "Magnesium sulphate versus diazepam for eclampsia". The Cochrane Database of Systematic Reviews. 2010 (12): CD000127. doi:10.1002/14651858.CD000127.pub2. PMC 7045443. PMID 21154341.
  26. ^ Duley L, Henderson-Smart DJ, Chou D (October 2010). "Magnesium sulphate versus phenytoin for eclampsia". The Cochrane Database of Systematic Reviews (10): CD000128. doi:10.1002/14651858.CD000128.pub2. PMID 20927719.
  27. ^ "Magnesium sulfate for preterm labor". 19 January 2007. Archived from the original on 24 June 2009. Retrieved 6 July 2009.
  28. ^ Lewis DF (September 2005). "Magnesium sulfate: the first-line tocolytic". Obstetrics and Gynecology Clinics of North America. 32 (3): 485–500. doi:10.1016/j.ogc.2005.03.002. PMID 16125045.
  29. ^ Simhan HN, Caritis SN (August 2007). "Prevention of preterm delivery". The New England Journal of Medicine. 357 (5): 477–487. doi:10.1056/NEJMra050435. PMID 17671256.
  30. ^ Grimes DA, Nanda K (October 2006). "Magnesium sulfate tocolysis: time to quit". Obstetrics and Gynecology. 108 (4): 986–989. doi:10.1097/01.AOG.0000236445.18265.93. PMID 17012463. S2CID 30014199.
  31. ^ "Magnesium Sulfate: Drug Safety Communication – Recommendation Against Prolonged Use in Pre-term Labor". FDA. Archived from the original on 3 June 2013. Retrieved 2 June 2013.
  32. ^ Doyle LW, Crowther CA, Middleton P, Marret S, Rouse D (January 2009). "Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus". The Cochrane Database of Systematic Reviews (1): CD004661. doi:10.1002/14651858.CD004661.pub3. PMID 19160238.
  33. ^ Wolf HT, Hegaard HK, Greisen G, Huusom L, Hedegaard M (February 2012). "Treatment with magnesium sulphate in pre-term birth: a systematic review and meta-analysis of observational studies". Journal of Obstetrics and Gynaecology. 32 (2): 135–140. doi:10.3109/01443615.2011.638999. PMID 22296422. S2CID 24012925.
  34. ^ Nguyen TM, Crowther CA, Wilkinson D, Bain E (February 2013). "Magnesium sulphate for women at term for neuroprotection of the fetus". The Cochrane Database of Systematic Reviews. 2 (2): CD009395. doi:10.1002/14651858.cd009395.pub2. PMID 23450601.
  35. ^ Shih ST, Tonmukayakul U, Imms C, Reddihough D, Graham HK, Cox L, Carter R (June 2018). "Economic evaluation and cost of interventions for cerebral palsy: a systematic review". Developmental Medicine and Child Neurology. 60 (6): 543–558. doi:10.1111/dmcn.13653. hdl:10536/DRO/DU:30106090. PMID 29319155.
  36. ^ "BARIUM CHLORIDE DIHYDRATE 4. First Aid Measures". Archived from the original on 9 July 2012. Retrieved 6 July 2009.{{cite web}}: CS1 maint: unfit URL (link)
  37. ^ Wood HC (1877). A Treatise on Therapeutics, Comprising Materia Medica and Toxicology, with Especial Reference to the Application of the Physiological Action of Drugs to Clinical Medicine. Philadelphia: J. B. Lippincott & Co. p. 34. The treatment of acute lead-poisoning consists in the evacuation of the stomach, if necessary, the exhibition of the sulphate of sodium or of magnesium, and the meeting of the indications as they arrive. The Epsom and Glauber's salts act as chemical antidotes, by precipitating the insoluble sulphate of lead, and also, if in excess, empty the bowel of the compound formed.
  38. ^ Rangan C (27 January 2016). Lead and Mercury (PDF). Children's Environmental Health Symposium San Diego 2016: Protecting Children's Environmental Health in the U.S.-Mexico Border Region. San Diego, CA: Environmental Protection Agency. Retrieved 2 August 2020.
  39. ^ Barker CA (January 1945). "Experience with Lead Poisoning". Canadian Journal of Comparative Medicine and Veterinary Science. 9 (1): 6–8. PMC 1660962. PMID 17648099. Udall (1) suggests sodium citrate as of some value together with Epsom salts which will bring about a precipitation of the lead in the form of an insoluble compound. Nelson (3) reported a case that survived following the use of a 20% magnesium sulphate solution intravenously, subcutaneously and orally. McIntosh (5) has suggested that purgative doses of Epsom salts may be effective in combining with the lead and overcoming the toxicity.
  40. ^ Herriot J (1972). All Creatures Great and Small. New York: St. Martin's Press. p. 157. ISBN 0-312-08498-6. The specific antidotes to metal poisoning had not been discovered and the only thing which sometimes did a bit of good was magnesium sulphate which caused the precipitation of insoluble lead sulphate. The homely term for magnesium sulphate is, of course, epsom salts.
  41. ^ Nath MP, Garg R, Talukdar T, Choudhary D, Chakrabarty A (July 2012). "To evaluate the efficacy of intrathecal magnesium sulphate for hysterectomy under subarachnoid block with bupivacaine and fentanyl: A prospective randomized double blind clinical trial". Saudi Journal of Anaesthesia. 6 (3): 254–258. doi:10.4103/1658-354x.101217. PMC 3498664. PMID 23162399.
  42. ^ Corkeron MA (April 2003). "Magnesium infusion to treat Irukandji syndrome". The Medical Journal of Australia. 178 (8): 411. doi:10.5694/j.1326-5377.2003.tb05263.x. PMID 12697017. S2CID 28335891.