From the FDA Drug Label
In paroxysmal atrial tachycardia, magnesium should be used only if simpler measures have failed and there is no evidence of myocardial damage. The usual dose is 3 to 4 g (30 to 40 mL of a 10% solution) administered IV over 30 seconds with extreme caution.
The recommended dose of magnesium to prevent supraventricular tachycardia (SVT) is 3 to 4 g administered IV over 30 seconds with extreme caution, but only if simpler measures have failed and there is no evidence of myocardial damage 1.
From the Research
The recommended dose of magnesium for preventing supraventricular tachycardia (SVT) is typically 2 grams of magnesium sulfate given intravenously, as this dose has been shown to be effective in some patients with SVT, particularly those with magnesium deficiency or digitalis toxicity 2, 3, 4.
Key Considerations
- When administering IV magnesium, patients should be monitored for hypotension, flushing, and respiratory depression, especially in those with renal impairment where dosage adjustments may be necessary.
- Magnesium works by stabilizing cardiac cell membranes and modulating calcium channels, which helps regulate electrical conduction in the heart.
- The efficacy of magnesium in preventing SVT may vary depending on the individual patient and the underlying cause of the arrhythmia.
Important Factors to Consider
- Magnesium deficiency or digitalis toxicity may increase the effectiveness of magnesium in preventing SVT.
- Patients with kidney disease should be cautious when using magnesium, and serum magnesium levels should be monitored during treatment to maintain therapeutic levels without reaching toxicity.
- The use of magnesium in preventing SVT should be individualized and based on the specific needs and circumstances of each patient.
Relevant Studies
- A study published in 1995 found that 2 grams of magnesium sulfate given intravenously was effective in terminating SVT in some patients, although it was less effective than verapamil 2.
- Another study published in 1992 found that magnesium sulfate was effective in terminating SVT in some patients, but was less effective than adenosine triphosphate 3.
- A study published in 1993 found that magnesium sulfate was effective in converting patients with supraventricular arrhythmias to sinus rhythm, and was at least as effective as verapamil 4.