Magnesium Chloride

Medically reviewed by Drugs.com. Last updated on Sep 6, 2020.

• Overview
• Side Effects
• Dosage
• Professional
• Interactions
• More

Pronunciation

(mag NEE zhum KLOR ide)

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Solution, Injection, as hexahydrate:

Chloromag: 200 mg/mL (50 mL [DSC]) [contains benzyl alcohol]

Generic: 200 mg/mL (50 mL)

Tablet, Oral:

Generic: Elemental magnesium 64 mg (plus calcium 112 mg)

Tablet Delayed Release, Oral:

Mag-SR Plus Calcium: 535 mg (elemental magnesium 64 mg, plus calcium 106 mg) [starch free, sugar free]

Magdelay: Elemental magnesium 70 mg (plus calcium 118 mg) [DSC]

Nu-Mag: Elemental magnesium 71.5 mg (plus calcium 119 mg) [contains fd&c blue #2 aluminum lake]

Slow Magnesium/Calcium: 535 mg (elemental magnesium 64 mg, plus calcium 106 mg)

Slow-Mag: Elemental magnesium 71.5 mg (plus calcium 119 mg) [contains fd&c blue #2 aluminum lake]

SlowMag Mg Muscle/Heart: Elemental magnesium 71.5 mg (plus calcium 119 mg) [contains fd&c blue #2 aluminum lake]

Brand Names: U.S.

• Chloromag [DSC]
• Mag-SR Plus Calcium [OTC]
• Magdelay [OTC] [DSC]
• Nu-Mag [OTC]
• Slow Magnesium/Calcium [OTC]
• Slow-Mag [OTC]
• SlowMag Mg Muscle/Heart [OTC]

Pharmacologic Category

• Electrolyte Supplement, Oral
• Electrolyte Supplement, Parenteral
• Magnesium Salt

Pharmacology

Magnesium is important as a cofactor in many enzymatic reactions in the body involving protein synthesis and carbohydrate metabolism (at least 300 enzymatic reactions require magnesium). Actions on lipoprotein lipase have been found to be important in reducing serum cholesterol and on sodium/potassium ATPase in promoting polarization (eg, neuromuscular functioning).

Absorption

Oral: Inversely proportional to amount ingested; 40% to 60% under controlled dietary conditions; 15% to 36% at higher doses

Distribution

Bone (50% to 60%); extracellular fluid (1% to 2%)

Excretion

Urine (as magnesium)

Protein Binding

30%, to albumin

Use: Labeled Indications

Correction or prevention of hypomagnesemia; dietary supplement

Contraindications

Hypersensitivity to any component of the formulation; renal impairment; myocardial disease; coma

Dosing: Adult

Note: Serum magnesium is poor reflection of repletional status as the majority of magnesium is intracellular; serum levels may be transiently normal for a few hours after a dose is given; therefore, aim for consistently high normal serum levels in patients with normal renal function for most efficient repletion.

Hypomagnesemia, prevention (parenteral nutrition supplementation) (ASPEN [Mirtallo 2004]): IV (elemental magnesium): 8 to 20 mEq/day

Dietary supplement: Oral (Mag 64, Mag-Delay, Slow-Mag): 2 tablets once daily

Dosing: Geriatric

Refer to adult dosing.

Dosing: Pediatric

Note: Dosing presented in mg and mEq, verify dosing units; 1,000 mg of magnesium chloride = 119.7 mg elemental magnesium = 9.85 mEq elemental magnesium = 4.93 mmol elemental magnesium; serum magnesium is poor reflection of repletional status as the majority of magnesium is intracellular; serum concentrations may be transiently normal for a few hours after a dose is given; therefore, aim for consistently high normal serum concentrations in patients with normal renal function for most efficient repletion.

Hypomagnesemia: Limited data available:

Infants, Children, and Adolescents: Dose expressed as elemental magnesium:

IV: 2.5 to 5 mg/kg/dose every 6 hours for 2 to 3 doses; dosing based on experience with magnesium sulfate salt which is preferred (Kliegman 2011).

Oral: Note: Achieving optimal magnesium levels using oral therapy may be difficult due to the propensity for magnesium to cause diarrhea; IV replacement may be more appropriate particularly in situations of severe deficit: 10 to 20 mg/kg/dose up to 4 times daily (Kliegman 2007).

Parenteral nutrition, maintenance magnesium requirement (ASPEN [Mirtallo 2004]): Note: Dose expressed as elemental magnesium:

Infants and Children ≤50 kg: IV: 0.3 to 0.5 mEq/kg/day as an additive to parenteral nutrition solution.

Children >50 kg and Adolescents: IV: 10 to 30 mEq/day as an additive to parenteral nutrition solution.

Reconstitution

Dilute magnesium chloride 4 g in 250 mL D₅W.

Administration

Oral: Bariatric surgery: Tablet, delayed release: Some institutions may have specific protocols that conflict with these recommendations; refer to institutional protocols as appropriate. ER tablets should be swallowed whole. Do not cut, chew, or crush. IR tablet and injectable formulations are available.

If safety and efficacy can be effectively monitored, no change in formulation or administration is required after bariatric surgery; however, clinicians should be aware that bariatric vitamin supplementation is recommended lifelong and may include magnesium. Consider integrating part or all of magnesium supplementation requirements into the postsurgery bariatric vitamin regimen.

Dietary Considerations

Whole grains, legumes, and dark-green leafy vegetables are dietary sources of magnesium.

Adequate intake (AI) (elemental magnesium) (IOM 1997):

1 to 6 months: 30 mg daily

7 to 12 months: 75 mg daily

Dietary recommended daily allowance (RDA) (elemental magnesium) (IOM 1997):

1 to 3 years: 80 mg/day

4 to 8 years: 130 mg/day

9 to 13 years: 240 mg/day

14 to 18 years:

Females: 360 mg/day

Pregnancy: 400 mg/day

Lactation: 360 mg/day

Males: 410 mg/day

19 to 30 years:

Females: 310 mg/day

Pregnancy: 350 mg/day

Lactation: 310 mg/day

Males: 400 mg/day

≥31 years:

Females: 320 mg/day

Pregnancy: 360 mg/day

Lactation: 320 mg/day

Males: 420 mg/day

Storage

Injection: Prior to reconstitution, store at controlled room temperature of 15°C to 30°C (59°F to 86°F).

Drug Interactions

Alfacalcidol: May increase the serum concentration of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving alfacalcidol. If magnesium-containing products must be used with alfacalcidol, serum magnesium concentrations should be monitored closely. Consider therapy modification

Alpha-Lipoic Acid: Magnesium Salts may decrease the absorption of Alpha-Lipoic Acid. Alpha-Lipoic Acid may decrease the absorption of Magnesium Salts. Management: Separate administration of alpha-lipoic acid from that of any magnesium-containing compounds by several hours. If alpha-lipoic acid is given 30 minutes before breakfast, then administer oral magnesium-containing products at lunch or dinner. Consider therapy modification

Baloxavir Marboxil: Polyvalent Cation Containing Products may decrease the serum concentration of Baloxavir Marboxil. Avoid combination

Bictegravir: Polyvalent Cation Containing Products may decrease the serum concentration of Bictegravir. Management: Administer bictegravir under fasting conditions at least 2 hours before or 6 hours after polyvalent cation containing products. Coadministration of bictegravir with or 2 hours after most polyvalent cation products is not recommended. Consider therapy modification

Bisphosphonate Derivatives: Polyvalent Cation Containing Products may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of oral medications containing polyvalent cations within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate. Consider therapy modification

Calcitriol (Systemic): May increase the serum concentration of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving calcitriol. If magnesium-containing products must be used with calcitriol, serum magnesium concentrations should be monitored closely. Consider therapy modification

Calcium Channel Blockers: May enhance the adverse/toxic effect of Magnesium Salts. Magnesium Salts may enhance the hypotensive effect of Calcium Channel Blockers. Monitor therapy

Deferiprone: Polyvalent Cation Containing Products may decrease the serum concentration of Deferiprone. Management: Separate administration of deferiprone and oral medications or supplements that contain polyvalent cations by at least 4 hours. Consider therapy modification

Dolutegravir: Magnesium Salts may decrease the serum concentration of Dolutegravir. Management: Administer dolutegravir at least 2 hours before or 6 hours after oral magnesium salts. Administer the dolutegravir/rilpivirine combination product at least 4 hours before or 6 hours after oral magnesium salts. Consider therapy modification

Doxercalciferol: May enhance the hypermagnesemic effect of Magnesium Salts. Management: Consider using a non-magnesium-containing antacid or phosphate-binding product in patients also receiving doxercalciferol. If magnesium-containing products must be used with doxercalciferol, serum magnesium concentrations should be monitored closely. Consider therapy modification

Eltrombopag: Polyvalent Cation Containing Products may decrease the serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any polyvalent cation containing product. Consider therapy modification

Elvitegravir: Polyvalent Cation Containing Products may decrease the serum concentration of Elvitegravir. Management: Administer elvitegravir 2 hours before or 6 hours after the administration of polyvalent cation containing products. Consider therapy modification

Gabapentin: Magnesium Salts may enhance the CNS depressant effect of Gabapentin. Specifically, high dose intravenous/epidural magnesium sulfate may enhance the CNS depressant effects of gabapentin. Magnesium Salts may decrease the serum concentration of Gabapentin. Management: Administer gabapentin at least 2 hours after use of a magnesium-containing antacid. Monitor patients closely for evidence of reduced response to gabapentin therapy. Monitor for CNS depression if high dose IV/epidural magnesium sulfate is used. Consider therapy modification

Levothyroxine: Magnesium Salts may decrease the serum concentration of Levothyroxine. Management: Separate administration of oral levothyroxine and oral magnesium salts by at least 4 hours. Consider therapy modification

Multivitamins/Fluoride (with ADE): Magnesium Salts may decrease the serum concentration of Multivitamins/Fluoride (with ADE). Specifically, magnesium salts may decrease fluoride absorption. Management: To avoid this potential interaction separate the administration of magnesium salts from administration of a fluoride-containing product by at least 1 hour. Consider therapy modification

Neuromuscular-Blocking Agents: Magnesium Salts may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy

PenicillAMINE: Polyvalent Cation Containing Products may decrease the serum concentration of PenicillAMINE. Management: Separate the administration of penicillamine and oral polyvalent cation containing products by at least 1 hour. Consider therapy modification

Phosphate Supplements: Magnesium Salts may decrease the serum concentration of Phosphate Supplements. Management: Administer oral phosphate supplements as far apart from the administration of an oral magnesium salt as possible to minimize the significance of this interaction. Consider therapy modification

Quinolones: Magnesium Salts may decrease the serum concentration of Quinolones. Management: Administer oral quinolones several hours before (4 h for moxi/pe/spar/enox-, 2 h for others) or after (8 h for moxi-, 6 h for cipro/dela-, 4 h for lome/pe/enox-, 3 h for gemi-, and 2 h for levo-, nor-, or ofloxacin or nalidixic acid) oral magnesium salts. Consider therapy modification

Raltegravir: Magnesium Salts may decrease the serum concentration of Raltegravir. Management: Avoid the use of oral / enteral magnesium salts with raltegravir. No dose separation schedule has been established that adequately reduces the magnitude of interaction. Avoid combination

Tetracyclines: Magnesium Salts may decrease the absorption of Tetracyclines. Only applicable to oral preparations of each agent. Management: Avoid coadministration of oral magnesium salts and oral tetracyclines. If coadministration cannot be avoided, administer oral magnesium at least 2 hours before, or 4 hours after, oral tetracyclines. Monitor for decreased tetracycline therapeutic effects. Consider therapy modification

Trientine: Polyvalent Cation Containing Products may decrease the serum concentration of Trientine. Management: Avoid concomitant administration of trientine and oral products that contain polyvalent cations. If oral iron supplements are required, separate the administration by 2 hours. If other oral polyvalent cations are needed, separate administration by 1 hour. Consider therapy modification

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.

Frequency not defined: Gastrointestinal: Diarrhea (excessive oral doses)

Warnings/Precautions

Disease-related concerns:

• Neuromuscular disease: Use with extreme caution in patients with myasthenia gravis or other neuromuscular disease.

• Renal impairment: Use with caution in patients with renal impairment; accumulation of magnesium may lead to magnesium intoxication.

Special populations:

• Obstetrics: Vigilant monitoring and safe administration techniques (ISMP Medication Safety Alert, 2005) recommended to avoid potential for errors resulting in toxicity. Monitor patient and fetal status, and serum magnesium levels closely.

Dosage form specific issues:

• Aluminum: The parenteral product may contain aluminum; toxic aluminum concentrations may be seen with high doses, prolonged use, or renal dysfunction. Premature neonates are at higher risk due to immature renal function and aluminum intake from other parenteral sources. Parenteral aluminum exposure of >4 to 5 mcg/kg/day is associated with CNS and bone toxicity; tissue loading may occur at lower doses (Federal Register, 2002). See manufacturer’s labeling.

• Benzyl alcohol and derivatives: Some dosage forms may contain benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP ["Inactive" 1997]; CDC, 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors, 2001); avoid or use dosage forms containing benzyl alcohol with caution in neonates. See manufacturer’s labeling.

Other warnings/precautions:

• Electrolyte abnormalities: Concurrent hypokalemia or hypocalcemia can accompany a magnesium deficit. Hypomagnesemia is associated with hypokalemia and requires correction in order to normalize potassium.

• Parenteral administration: Monitor serum magnesium level, respiratory rate, blood pressure, deep tendon reflex, and renal function when administered parenterally, particularly with repeated dosing; magnesium toxicity can lead to fatal cardiovascular arrest and/or respiratory paralysis.

Monitoring Parameters

IV: Rapid administration: ECG monitoring, vital signs, deep tendon reflexes; magnesium, calcium, and potassium levels; renal function during administration

Oral: Renal function; magnesium levels; bowel movements

Pregnancy Risk Factor

C

Pregnancy Considerations

Animal reproduction studies have not been conducted. Magnesium crosses the placenta; serum levels in the fetus correlate with those in the mother (Idama, 1998; Osada, 2002).

Patient Education

What is this drug used for?

• It is used to treat or prevent low magnesium levels.

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Diarrhea

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

All products:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Injection:

• Flushing

• Sweating a lot

• Dizziness or passing out

• Feeling sluggish

• Feeling cold

• Shortness of breath

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine’s uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

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