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Citrate of Magnesia Side Effects

Generic name: magnesium citrate

Note: This document contains side effect information about magnesium citrate. Some dosage forms listed on this page may not apply to the brand name Citrate of Magnesia.

Applies to magnesium citrate: oral capsule, oral liquid, oral tablet, oral tablet chewable.


Follow all directions on the label and package. Use exactly as directed.

Get emergency medical help if you have signs of an allergic reaction: hives, difficult breathing, swelling of your face, lips, tongue, or throat.

Stop using magnesium citrate (the active ingredient contained in Citrate of Magnesia) and call your doctor at once if you have:

Common side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to magnesium citrate: compounding powder, oral capsule, oral liquid, oral tablet, oral tablet chewable.


Mild hypermagnesemia is generally well-tolerated. Moderate or severe hypermagnesemia affects the nervous and cardiovascular systems primarily.[Ref]

Nervous system

Nervous system side effects have included a decrease in tendon reflexes, muscle weakness, mental confusion, sedation, mental depression, areflexia, coma and respiratory paralysis. CNS depression, often presenting as somnolence, may be more likely and more severe in patients with renal dysfunction.[Ref]

Nervous system side effects from hypermagnesemia result from suppression of neuromuscular transmission in the CNS and at the neuromuscular junction (which can be antagonized by calcium). Clinically, if serum magnesium (Mg) levels increase to 4 to 7 mEq/L, there may be a decrease in tendon reflexes, muscle weakness, and/or mental confusion or sedation. At levels of 5 to 10 mEq/L, the respiratory rate slows and blood pressure falls. At levels of 10 to 15 mEq/L, there is usually profound mental depression, areflexia, coma and respiratory paralysis. Mg also has a curare-like effect at the neuromuscular junction at serum levels above 10 mEq/L. Death is not uncommon when serum Mg levels rise to 15 mEq/L.[Ref]


Cardiovascular side effects have included hypotension, depressed myocardial conductivity, asystole, and bradyarrhythmias.[Ref]

The cardiovascular consequences of hypermagnesemia are due to peripheral vasodilation. Hypotension may be observed when serum Mg levels rise to 5 to 10 mEq/L. Hypotension, depressed myocardial conductivity, and bradyarrhythmias may be associated with levels greater than 10 mEq/L. While some patients are inexplicably able to tolerate extraordinarily high Mg levels, there is a significant risk of asystole when levels rise to 25 mEq/L. The risk of cardiotoxicity from hypermagnesemia is increased in the presence of hypocalcemia, hyperkalemia, acidosis, digitalis therapy, and renal insufficiency.[Ref]


Metabolic side effects have included hypocalcemia. The effects of hypermagnesemia may be worsened by the presence of hypocalcemia, especially in patients with uremia.[Ref]

A metabolic concern in the case of acute hypermagnesemia is hypocalcemia. Elevated Mg may cause hypocalcemia due to suppression of the release of parathyroid hormone (PTH) and competition for renal tubular reabsorption between calcium (Ca) and Mg. The latter can lead to decreased Ca reabsorption and hypercalciuria, which aggravates the hypocalcemia produced by decreased release of PTH.[Ref]


Gastrointestinal side effects have included nausea, and paralytic ileus (rarely).[Ref]

Gastrointestinal side effects include nausea when serum Mg levels rise to 4 to 5 mEq/L.

Rare cases of paralytic ileus associated with serum Mg levels greater than 5 mEq/L have been reported.[Ref]

Frequently asked questions


1. Lembcke B, Fuchs C. Magnesium load induced by ingestion of magnesium-containing antacids. Contrib Nephrol. 1984;38:185-94.

2. Alison LH, Bulugahapitiya D. Laxative induced magnesium poisoning in a 6 week old infant. BMJ. 1990;300:125.

3. Jenny DB, Goris GB, Urwiller RD, Brian BA. Hypermagnesemia following irrigation of renal pelvis. Cause of respiratory depression. JAMA. 1978;240:1378-9.

4. Schrier RW, Gottschalk CW, Eds. Diseases of the Kidney, 5th Edition. Boston, MA: Little, Brown and Company. 1993;1-3:183-2653.

5. Wilson J, Braunwald E, Isselbacher K, Petersdorf R, Martin J, Fauci A, Root R. Harrison's Principles of Internal Medicine, 12th Edition. McGraw-Hill, Inc., Health Professions Division, New York. 1991;1:1938.

6. Cumming WA, Thomas VJ. Hypermagnesemia: a cause of abnormal metaphyses in the neonate. AJR Am J Roentgenol. 1989;152:1071-2.

7. Golzarian J, Scott HW, Richards WO. Hypermagnesemia-induced paralytic ileus. Dig Dis Sci. 1994;39:1138-42.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.