(mag NEE zhum KLOR ide)
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) [contains benzyl alcohol]
Generic: 200 mg/mL (50 mL)
Tablet Delayed Release, Oral:
Mag-SR Plus Calcium: 535 mg (elemental magnesium 64 mg, plus calcium 106 mg) [starch free, sugar free]
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]
Tablet Extended Release, Oral:
Mag-Delay: 535 mg (elemental magnesium 64 mg)
Mag-SR: 535 mg (elemental magnesium 64 mg) [DSC] [starch free, sugar free]
Brand Names: U.S.
- Mag-Delay [OTC]
- Mag-SR Plus Calcium [OTC]
- Mag-SR [OTC] [DSC]
- Slow Magnesium/Calcium [OTC]
- Slow-Mag [OTC]
- Electrolyte Supplement, Oral
- Electrolyte Supplement, Parenteral
- Magnesium Salt
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).
Oral: Inversely proportional to amount ingested; 40% to 60% under controlled dietary conditions; 15% to 36% at higher doses
Bone (50% to 60%); extracellular fluid (1% to 2%)
Urine (as magnesium)
30%, to albumin
Use: Labeled Indications
Correction or prevention of hypomagnesemia; dietary supplement
Hypersensitivity to any component of the formulation; renal impairment; myocardial disease; coma
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.
Dietary supplement: Adults: Oral (Mag 64®, Mag Delay™, Slow-Mag®): 2 tablets once daily
Hypomagnesemia, prevention (parenteral nutrition supplementation) (ASPEN [Mirtallo, 2004]): IV (elemental magnesium):
Infants, Children, and Adolescents:
≤50 kg: 0.3 to 0.5 mEq/kg/day
>50 kg: 10 to 30 mEq/day
Adults: 8 to 20 mEq/day
RDA (elemental magnesium) (IOM, 1997): Oral:
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
Females: 320 mg/day
Pregnancy: 360 mg/day
Lactation: 320 mg/day
Males: 420 mg/day
Dosage adjustment in renal impairment: According to the manufacturer’s labeling, use is contraindicated in patients with renal impairment
Dosage adjustment in hepatic impairment: No dosage adjustment provided in manufacturer’s labeling.
Dilute magnesium chloride 4 g in 250 mL D5W.
Whole grains, legumes, and dark-green leafy vegetables are dietary sources of magnesium.
Injection: Prior to reconstitution, store at controlled room temperature of 15°C to 30°C (59°F to 86°F).
Alfacalcidol: May increase the serum concentration of Magnesium Salts. 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. Consider therapy modification
Bisphosphonate Derivatives: Magnesium Salts may decrease the serum concentration of Bisphosphonate Derivatives. Management: Avoid administration of oral magnesium salts within: 2 hours before or after tiludronate/clodronate/etidronate; 60 minutes after oral ibandronate; or 30 minutes after alendronate/risedronate. Exceptions: Pamidronate; Zoledronic Acid. Consider therapy modification
Calcitriol (Systemic): May increase the serum concentration of Magnesium Salts. 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: Magnesium Salts 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. Consider therapy modification
Eltrombopag: Magnesium Salts may decrease the serum concentration of Eltrombopag. Management: Administer eltrombopag at least 2 hours before or 4 hours after oral administration of any magnesium-containing product. 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 oral magnesium salts administration. 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
Mycophenolate: Magnesium Salts may decrease the serum concentration of Mycophenolate. Management: Separate doses of mycophenolate and oral magnesium salts. Monitor for reduced effects of mycophenolate if taken concomitant with oral magnesium salts. Consider therapy modification
Neuromuscular-Blocking Agents: Magnesium Salts may enhance the neuromuscular-blocking effect of Neuromuscular-Blocking Agents. Monitor therapy
Phosphate Supplements: Magnesium Salts may decrease the serum concentration of Phosphate Supplements. Management: This applies only to oral phosphate and magnesium administration. Administer oral phosphate supplements at least 1 hour before, or 2 hours after, oral magnesium salt administration. Exceptions: Sodium Glycerophosphate Pentahydrate. Consider therapy modification
Quinolone Antibiotics: Magnesium Salts may decrease the serum concentration of Quinolone Antibiotics. Management: Administer oral quinolones at least several hours before (4 h for moxi- and sparfloxacin, 2 h for others) or after (8 h for moxi-, 6 h for cipro-, 4 h for lome-, 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
Tetracycline Derivatives: Magnesium Salts may decrease the absorption of Tetracycline Derivatives. Only applicable to oral preparations of each agent. Consider therapy modification
Trientine: May decrease the serum concentration of Magnesium Salts. Magnesium Salts may decrease the serum concentration of Trientine. Consider therapy modification
Frequency not defined: Gastrointestinal: Diarrhea (excessive oral doses)
• 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.
• 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.
• 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.
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
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).
• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
• Have patient report immediately to prescriber severe nausea or significant diarrhea (HCAHPS).
• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.
Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for healthcare professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience and judgment in diagnosing, treating and advising patients.
More about magnesium chloride
- Other brands: Chloromag