Magnesium (medical use)

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INN: Magnesium ion
CAS Number
PubChem CID
Chemical and physical data
Molar mass24.305 g·mol−1

Magnesium salts are available as a medication in a number of formulations. They are used to treat magnesium deficiency, low blood magnesium, eclampsia, and several other conditions. Magnesium is important to health.

Usually in lower dosages, magnesium is commonly included in dietary mineral preparations, including many multivitamin preparations. Chelated magnesium is sometimes used to aid in absorption.

In 2020, it was the 202nd most commonly prescribed medication in the United States, with more than 2 million prescriptions.[1][2]

Medical uses[edit]

  • As a bronchodilator after beta-agonist and anticholinergic agents have been tried, e.g. in severe exacerbations of asthma.[3] Recent studies have revealed that magnesium sulfate can be nebulized to reduce the symptoms of acute asthma.[3] It is commonly administered via the intravenous route for the management of severe asthma attacks.
  • Obstetrics: Magnesium sulfate is used to prevent seizures in women with preeclampsia and eclampsia, and is also used for fetal neuroprotection in preterm deliveries, but has been shown to be an ineffective tocolytic agent.[4][5]

Side effects[edit]

More common side effects from magnesium include upset stomach and diarrhea, and calcium deficiency if calcium levels are already low.[6]


Overdose of magnesium (hypermagnesemia) is only possible in special circumstances. It can cause diarrhea,[7] nausea, vomiting, severely lowered blood pressure, confusion, slowed heart rate, respiratory paralysis.[6] In very severe cases, it can cause coma, cardiac arrhythmia, cardiac arrest and death.[6]

Magnesium overdose can be counteracted by administering calcium gluconate.[8]

Types of preparations[edit]

In practice, magnesium is given in a salt form together with any of several anionic compounds serving as counter-ions, such as chloride or sulfate. Nevertheless, magnesium is generally presumed to be the active component. An exception is the administration of magnesium sulfate in barium chloride poisoning,[24] where sulfate binds to barium to form insoluble barium sulfate.

Magnesium is absorbed orally at about 30% bioavailability from any water soluble salt, such as magnesium chloride or magnesium citrate. The citrate is the least expensive soluble (high bioavailability) oral magnesium salt available in supplements, with 100 mg and 200 mg magnesium typically contained per capsule, tablet or 50 mg/mL in solution.[25]

Magnesium aspartate, chloride, lactate, citrate and glycinate each have bioavailability 4 times greater than the oxide form and are equivalent to each other per amount of magnesium, though not in price.[26][27]

The ligand of choice for large-scale manufacturers of multivitamins and minerals containing magnesium is the magnesium oxide due to its compactness, high magnesium content by weight, low cost, and ease-of-use in manufacturing. However it is insoluble in water. Insoluble magnesium salts such as magnesium oxide or magnesium hydroxide (milk of magnesia) depend on stomach acid for neutralization before they can be absorbed, and thus are relatively poor oral magnesium sources, on average.

Magnesium sulfate (Epsom salts) is soluble in water. It is commonly used as a laxative, owing to the poor absorption of the sulfate component. In lower doses, they may be used as an oral magnesium source, however.

Intravenous or intramuscular magnesium is generally in the form of magnesium sulfate solution. Intravenous or intramuscular magnesium is completely bioavailable, and effective. It is used in severe hypomagnesemia and eclampsia.


Research on topical magnesium (for example epsom salt baths) is very limited.[28][29]

See also[edit]


  1. ^ "The Top 300 of 2020". ClinCalc. Retrieved 7 October 2022.
  2. ^ "Magnesium - Drug Usage Statistics". ClinCalc. Retrieved 7 October 2022.
  3. ^ 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.
  4. ^ "Committee Opinion No 652: Magnesium Sulfate Use in Obstetrics". Obstetrics and Gynecology. 127 (1): e52–e53. January 2016. doi:10.1097/AOG.0000000000001267. PMID 26695587. S2CID 33483604.
  5. ^ Crowther CA, Brown J, McKinlay CJ, Middleton P (August 2014). "Magnesium sulphate for preventing preterm birth in threatened preterm labour". The Cochrane Database of Systematic Reviews (8): CD001060. doi:10.1002/14651858.CD001060.pub2. PMID 25126773.
  6. ^ a b c Ehrlich SD (17 June 2011). "Magnesium". at University of Maryland Medical Center (UMMCb. Archived from the original on 27 January 2011.
  7. ^ "Health Risks from Excessive Magnesium". Office of Dietary Supplements (ODS). U.S. National Institutes of Health (NIH).
  8. ^ Omu AE, Al-Harmi J, Vedi HL, Mlechkova L, Sayed AF, Al-Ragum NS (2008). "Magnesium sulphate therapy in women with pre-eclampsia and eclampsia in Kuwait". Medical Principles and Practice. 17 (3): 227–232. doi:10.1159/000117797. PMID 18408392.
  9. ^ "Magnesium Aspartate HCl Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  10. ^ "Magnesium Carbonate Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  11. ^ "Magnesium Chloride Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  12. ^ "Magnesium Gluconate: MedlinePlus Drug Information".
  13. ^ "Magnesium Glycinate Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  14. ^ "Magnesium Lactate Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  15. ^ "Mg-Orotate Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  16. ^ "Magnesium Oxide Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  17. ^ "Magnesium Carbonate - an overview | ScienceDirect Topics".
  18. ^ "Magnesium Citrate Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  19. ^ "Magnesium Citrate: MedlinePlus Drug Information".
  20. ^ "Magnesium Citrate - an overview | ScienceDirect Topics".
  21. ^ "Magnesium Hydroxide Oral: Uses, Side Effects, Interactions, Pictures, Warnings & Dosing - WebMD".
  22. ^ "Magnesium Oxide: MedlinePlus Drug Information".
  23. ^ "Health Benefits of Magnesium Oxide". WebMD.
  24. ^ "BARIUM CHLORIDE DIHYDRATE 4. First Aid Measures". Retrieved 6 July 2009.
  25. ^ "Rougier Pharma Citro Mag Laxatif/purgatif – CTC Health". Retrieved 30 November 2022.
  26. ^ Firoz M, Graber M (December 2001). "Bioavailability of US commercial magnesium preparations". Magnesium Research. 14 (4): 257–62. PMID 11794633.
  27. ^ Lindberg JS, Zobitz MM, Poindexter JR, Pak CY (February 1990). "Magnesium bioavailability from magnesium citrate and magnesium oxide". Journal of the American College of Nutrition. 9 (1): 48–55. doi:10.1080/07315724.1990.10720349. PMID 2407766.
  28. ^ "Magnesium Oil Benefits: Forms, Benefits, Uses, and Risks". Healthline. 25 January 2021.
  29. ^ Rath, Linda. "Why Take an Epsom Salts Bath?". WebMD.