Magnesium (medical use)

Magnesium
INN: Magnesium ion
Identifiers
CAS Number
PubChem CID
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Chemical and physical data
Formula Mg+2
Molar mass 24.31 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.

Medical uses

  • As a bronchodilator after beta-agonist and anticholinergic agents have been tried, e.g. in severe exacerbations of asthma.[1] Recent studies have revealed that magnesium sulfate can be nebulized to reduce the symptoms of acute asthma.[1] 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.[2][3]
  • Mild cognitive impairment. Magnesium l-threonate is able to deliver high amounts of magnesium to the central nervous system and has in animal studies as well as human trials shown efficacy in treating cognitive impairment.[4][5] The results of these studies are well in line with systematic reviews showing that Alzheimer’s patients have lower magnesium status when compared to healthy controls.[6]

Side effects

More common side effects from magnesium include upset stomach and diarrhea, and calcium deficiency if calcium levels are already low.[7]

Overdose

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

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

Types of preparations

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,[9] 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 or tablet.

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.[10][11]

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.

Magnesium l-threonate is a new magnesium preparation that in preclinical animal studies has shown great promise as a treatment of mild cognitive impairment.[4] Its efficacy and safety has now been replicated in the first double-blind placebo controlled human trial.[5] However, said study mentions as part of its limitations the fact that all of the participants suffered anxiety and sleep disorders together with cognitive impairment. This suggests that the results could be attributed simply to a replenishment of depleted elemental magnesium in the body. Also, three authors of the paper have significant conflicts of interest.[12]

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.

References

  1. 1 2 Blitz M, Blitz S, Hughes R, Diner B, Beasley R, Knopp J, Rowe BH (2005). "Aerosolized magnesium sulfate for acute asthma: a systematic review". Chest. 128 (1): 337–44. doi:10.1378/chest.128.1.337. PMID 16002955.
  2. ↑ "Committee Opinion No 652: Magnesium Sulfate Use in Obstetrics". Obstetrics and Gynecology. 127 (1): e52–53. 2016-1. doi:10.1097/AOG.0000000000001267. ISSN 1873-233X. PMID 26695587. Check date values in: |date= (help)
  3. ↑ Crowther, Caroline A.; Brown, Julie; McKinlay, Christopher J. D.; Middleton, Philippa (2014-08-15). "Magnesium sulphate for preventing preterm birth in threatened preterm labour". The Cochrane Database of Systematic Reviews (8): CD001060. doi:10.1002/14651858.CD001060.pub2. ISSN 1469-493X. PMID 25126773.
  4. 1 2 Li W, Yu J, Liu Y, Huang X, Abumaria N, Zhu Y, Huang X, Xiong W, Ren C, Liu XG, Chui D, Liu G (2014). "Elevation of brain magnesium prevents synaptic loss and reverses cognitive deficits in Alzheimer's disease mouse model". Molecular Brain. 7 (65): 1–20. doi:10.1186/s13041-014-0065-y. PMC 4172865. PMID 25213836.
  5. 1 2 Liu G, Weinger JG, Lu ZL, Xue F, Sadeghpour S (2015). "Efficacy and safety of MMFS-01, a synapse density enhancer, for treating cognitive impairment in older adults: a randomized, double-blind, placebo-controlled trial". Journal of Alzheimer's Disease. 49 (4): 971–990. doi:10.3233/JAD-150538. PMC 4927823. PMID 26519439.
  6. ↑ Veronese N, Zurlo A, Solmi M, Luchini C, Trevisan C, Bano G, Manzato E, Sergi G, Rylander R (2016). "Magnesium Status in Alzheimer's Disease: A Systematic Review". American journal of Alzheimer's disease and other dementias. 31 (3): 208–213. doi:10.1177/1533317515602674. PMID 26351088.
  7. 1 2 3 Magnesium at University of Maryland Medical Center (UMMC). Reviewed last on: 6/17/2011 by Steven D. Ehrlich
  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". Med Princ Pract. 17 (3): 227–32. doi:10.1159/000117797. PMID 18408392.
  9. ↑ "BARIUM CHLORIDE DIHYDRATE 4. First Aid Measures". Jtbaker.com. Retrieved 2009-07-06.
  10. ↑ Firoz M, Graber M: "Bioavailability of US commercial magnesium preparations.", Magnesium Research 2001 Dec;14(4):257-62.
  11. ↑ Lindberg JS, Zobitz MM, Poindexter JR, Pak CY: "Magnesium bioavailability from magnesium citrate and magnesium oxide.", J Am Coll Nutr. 1990 Feb;9(1):48-55.
  12. ↑ "Efficacy and safety of MMFS-01, a synapse density enhancer, for treating cognitive impairment in older adults: a randomized, double-blind, placebo-controlled trial | Journal of Alzheimer's Disease". www.j-alz.com. Retrieved 2018-09-04.

See also

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