Indications for Magnesium Tablets
Magnesium tablets are primarily indicated for the treatment of hypomagnesemia, prevention and treatment of magnesium deficiency in high-risk patients, and as adjunctive therapy for specific conditions including migraine, cardiac arrhythmias, and constipation. 1
Primary Indications
- Hypomagnesemia treatment: Oral magnesium oxide (typically containing 60% elemental magnesium) is recommended for treating magnesium deficiency, with standard dosing of 12-24 mmol daily 1
- Replacement therapy: Magnesium supplementation is indicated for magnesium deficiency, especially in acute hypomagnesemia with signs of tetany similar to hypocalcemia 2
- Prevention of deficiency: Supplementation may be indicated when serum magnesium levels fall below the normal range (1.5 to 2.5 mEq/L) 2
Cardiovascular Indications
- Polymorphic ventricular tachycardia (Torsades de Pointes): Magnesium is indicated for polymorphic VT associated with QT prolongation, though IV administration (1-2g over 15 minutes) is preferred in acute settings 3
- Arrhythmia prevention: Magnesium supplementation may reduce ventricular arrhythmias, particularly in patients with heart failure experiencing diuresis-induced hypomagnesemia 3
- Cardiac monitoring: Patients with moderate to severe magnesium imbalances should be monitored electrocardiographically to prevent or intervene for potentially lethal cardiac rhythms 3
Neurological Indications
- Migraine prophylaxis: Strong evidence supports magnesium supplementation in migraine sufferers, particularly those with magnesium deficiency (which may affect up to half of migraine patients) 4
- Seizure prevention: In specific conditions like pre-eclampsia and eclampsia, magnesium is indicated for seizure prevention and control, though IV administration is typically used in acute settings 2
Other Clinical Indications
- Metabolic syndrome: Magnesium supplementation may lower the risk of metabolic syndrome and improve glucose and insulin metabolism 5
- Premenstrual syndrome: Magnesium may alleviate symptoms of PMS related to mood changes 6
- Dysmenorrhea: Evidence supports magnesium for relieving symptoms of menstrual pain 5
- Constipation: Magnesium oxide is commonly used at doses of 400-500 mg daily for chronic idiopathic constipation 1
- Leg cramps during pregnancy: Magnesium supplementation may help alleviate leg cramps in pregnant women 5
- Asthma: Magnesium has shown effectiveness in treating severe asthma 5
Special Populations
- 22q11.2 Deletion Syndrome: Daily calcium and magnesium supplementation is recommended for patients with this syndrome who commonly experience hypomagnesemia 3
- Patients on diuretics: Supplementation may be indicated for patients on diuretic therapy who are at risk for magnesium depletion 3
Dosing Considerations
- Standard dosing: Oral magnesium oxide is typically administered as 4 mmol (160 mg MgO) capsules, with total daily doses of 12-24 mmol for hypomagnesemia treatment 1
- Timing: Oral magnesium is best administered at night when intestinal transit is slower, allowing more time for absorption 1
- Cautions: Magnesium should be used with caution in patients with renal insufficiency as it is excreted renally 1
- Monitoring: Magnesium levels should be followed if frequent or prolonged dosing is required, particularly in patients with impaired renal function 3
Potential Adverse Effects
- Gastrointestinal: Diarrhea is the most common side effect of oral magnesium supplementation 5
- Severe toxicity: At high doses, magnesium can cause hypotension, CNS toxicity, and respiratory depression 3
- Cardiac effects: Severely elevated levels (6-10 mmol/L) may result in atrioventricular nodal conduction block, bradycardia, hypotension, and cardiac arrest 3