eMedicine Specialties > Pediatrics: General Medicine > Endocrinology
Hypermagnesemia: Treatment & Medication
Updated: May 5, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Treatment
Medical Care
- Symptoms and signs of magnesium intoxication respond to intravenous calcium. Calcium chloride (5 mL of a 10% sol) may be administered intravenously over 30 seconds to directly antagonize the cardiac and neuromuscular effects of excess extracellular magnesium. Monitor these patients in an ICU setting and give careful attention to ECG parameters.
- In order to promote a more sustained decrease in serum magnesium, patients with normal urine output and renal function may be treated with intravenous saline infusions and furosemide diuresis.
- Dialysis for hypermagnesemia may be used for patients with the following:
- Renal insufficiency
- Severe asymptomatic hypermagnesemia (>8 mEq/L)
- Serious cardiovascular or neuromuscular symptoms at any serum magnesium level
- Cathartics or enemas that do not contain magnesium may be used to enhance gastrointestinal clearance of excess ingested magnesium.
Consultations
- A nephrology consult may be obtained for refractory cases of hypermagnesemia or for patients with hypermagnesemia who require urgent dialysis.
Diet
- Advise the patient with hypermagnesemia to discontinue oral laxatives, antacids, or other preparations that contain magnesium.
Medication
Treatment depends on the degree of hypermagnesemia and the presence of symptoms. In patients with mildly increased levels, the source of magnesium may simply be removed. In patients with higher concentrations of magnesium or severe symptoms, other treatments are necessary. Reserve calcium for patients with life-threatening symptoms, such as arrhythmias or severe respiratory depression.
Intravenous fluids
Dilution of the extracellular magnesium concentration is the rationale behind intravenous use. Fluids are used with diuretics to promote diuresis of magnesium by the kidneys.
0.9% sodium chloride (normal saline)
Isotonic fluid. Restores water and sodium chloride losses.
Adult
Pediatric
<10 kg: 100 mL/kg/d
10-20 kg: 50 mL/kg/d
>20 kg: 20 mL/kg/d
May decrease levels of lithium when administered concurrently
Fluid retention; hypernatremia, hypertonic uterus; impaired renal or cardiac function
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in congestive heart failure, hypertension, edema, liver cirrhosis, renal insufficiency, and sodium toxicity
Diuretics
These agents increase renal excretion of magnesium.
Furosemide (Lasix)
Increases excretion of water by interfering with chloride-binding cotransport system, which inhibits sodium and chloride reabsorption in the ascending loop of Henle and distal renal tubule. Promotes loss of magnesium. Administer PO dose with food or milk to decrease stomach upset.
Adult
20-80 mg/dose IV; not to exceed 6 mg/kg/dose; titrate to effect
Pediatric
1 mg/kg/dose q6-12h prn; titrate to effect
Nephrotoxicity of cephalosporins increased; ototoxicity may be increased with concomitant administration of aminoglycosides; metformin decreases furosemide concentrations; furosemide interferes with hypoglycemic effect of antidiabetic agents and antagonizes muscle-relaxing effect of tubocurarine; anticoagulant activity of warfarin may be enhanced when taken concurrently; increased plasma lithium levels and toxicity are possible when taken concurrently
Documented hypersensitivity; hepatic coma, anuria, state of severe electrolyte depletion, hypokalemia, and renal failure
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Monitor serum electrolytes (eg, potassium), carbon dioxide, glucose, creatinine, uric acid, calcium, and BUN determinations during first few months of therapy and periodically thereafter; closely monitor serum potassium levels; may produce intravascular dehydration, severe hypokalemia, significant hypochloremic metabolic alkalosis, hyperuricemia, and deafness due to ototoxicity
Calcium
Calcium directly antagonizes the effects of magnesium.
Calcium chloride (10% sol)
Moderates nerve and muscle performance by regulating action potential excitation threshold. Dose expressed in calcium chloride, not elemental calcium.
Adult
2-4 mg/kg IV acutely over 10 min
2-4 mg/kg/h continuous infusion
Pediatric
20 mg/kg IV, may repeat in 10 min if necessary
Coadministration with digoxin may cause arrhythmias; with thiazides, may induce hypercalcemia; may antagonize effects of calcium channel blockers, atenolol, and sodium polystyrene sulfonate
Ventricular fibrillation not associated with hyperkalemia; digitalis toxicity, hypercalcemia, renal insufficiency, or cardiac disease
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Do not administer >50 mg/min; do not administer IM/SC
Do not administer IV calcium >30-60 mg elemental calcium/min
Rapid IV administration leads to hypotension, bradycardia, and asystole
More on Hypermagnesemia |
| Overview: Hypermagnesemia |
| Differential Diagnoses & Workup: Hypermagnesemia |
 Treatment & Medication: Hypermagnesemia |
| Follow-up: Hypermagnesemia |
| Multimedia: Hypermagnesemia |
| References |
| Further Reading |
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References
Reinhart RA. Magnesium metabolism. Arch Int Med. 1988;148:2415-2420. [Medline].
Musso CG. Magnesium metabolism in health and disease. Int Urol Nephrol. Mar 10 2009;[Medline].
Kaze Folefack F, Stoermann Chopard C. [Magnesium metabolism disturbances]. Rev Med Suisse. Mar 7 2007;3(101):605-6, 608, 610-1. [Medline].
Moe SM. Disorders involving calcium, phosphorus, and magnesium. Prim Care. Jun 2008;35(2):215-37, v-vi. [Medline].
Navarro-Gonzalez JF, Mora-Fernandez C, Garcia-Perez J. Clinical implications of disordered magnesium homeostasis in chronic renal failure and dialysis. Semin Dial. Jan-Feb 2009;22(1):37-44. [Medline].
[Best Evidence] Ford AA, Wylie BJ, Waksmonski CA, Simpson LL. Maternal congenital cardiac disease: outcomes of pregnancy in a single tertiary care center. Obstet Gynecol. Oct 2008;112(4):828-33. [Medline].
Corbi G, Acanfora D, Iannuzzi GL, et al. Hypermagnesemia predicts mortality in elderly with congestive heart disease: relationship with laxative and antacid use. Rejuvenation Res. Feb 2008;11(1):129-38. [Medline].
Ali A, Walentik C, Mantych GJ, et al. Iatrogenic acute hypermagnesemia after total parenteral nutrition infusion mimicking septic shock syndrome: two case reports. Pediatrics. Jul 2003;112(1 Pt 1):e70-2. [Medline].
Durham D, Worthley LI. Cardiac arrhythmias: diagnosis and management. The tachycardias. Crit Care Resusc. Mar 2002;4(1):35-53. [Medline].
Henyan NN, Gillespie EL, White CM, et al. Impact of intravenous magnesium on post-cardiothoracic surgery atrial fibrillation and length of hospital stay: a meta-analysis. Ann Thorac Surg. Dec 2005;80(6):2402-6. [Medline].
Knochel JP. Disorders of magnesium metabolism. Harrison's Principles of Internal Medicine. 1994;2:2187-2189. [Medline].
Nadler JL, Rude RK. Disorders of magnesium metabolism. Clinical Disorders of Fluid and Electrolyte Metabolism. 1995;24:623-637. [Medline].
Rude RK, Singer FR. Magnesium deficiency and excess. Ann Rev Med. 1981;32:245-259. [Medline].
Further Reading
- Relevant clinical guidelines include the following:
- Relevant clinical trials include the following:
- Related eMedicine topics include the following:
- Hypermagnesemia (Nephrology)
- Hypermagnesemia (Emergency Medicine)
- Renal Failure, Chronic and Dialysis Complications
- Hypoparathyroidism
- Hypomagnesemia
Keywords
hypermagnesemia, magnesium, Mg, elevated serum magnesium, acute renal failure, fatal hypermagnesemia, diabetic ketoacidosis, dehydration, pregnancy-induced hypertension, renal insufficiency, eclampsia, respiratory depression, heart block, asystole, hypotension, treatment, diagnosis
