What is the recommended intravenous (IV) dose and rate of magnesium for acute asthma exacerbation?

From the Guidelines

For acute severe asthma exacerbations, intravenous magnesium sulfate should be administered at a dose of 2 grams (or 25-75 mg/kg in children) diluted in 50-100 mL of normal saline and infused over 20 minutes, as recommended by the most recent and highest quality study 1.

Key Considerations

• The dose and rate of administration are crucial to minimize the risk of hypotension and other side effects.
• Magnesium works as a bronchodilator by relaxing smooth muscle through calcium channel blocking effects and may reduce inflammation.
• It's typically reserved for patients who have not responded adequately to standard treatments like inhaled beta-agonists, anticholinergics, and systemic corticosteroids.

Administration and Monitoring

• The infusion should not be given as a rapid bolus due to the risk of hypotension.
• Patients should be monitored during administration for potential side effects including hypotension, flushing, and respiratory depression.
• Checking magnesium levels before repeat dosing is advisable, though a single dose is generally safe even without baseline levels.

Contraindications and Precautions

• Contraindications include renal failure, heart block, and myasthenia gravis.
• Magnesium should be considered as an adjunct therapy rather than first-line treatment for severe asthma exacerbations, as supported by previous studies 1.

From the FDA Drug Label

DOSAGE & ADMINISTRATION Dosage of magnesium sulfate must be carefully adjusted according to individual requirements and response, and administration of the drug should be discontinued as soon as the desired effect is obtained. The rate of IV injection should generally not exceed 150 mg/minute (1. 5 mL of a 10% concentration or its equivalent)

The recommended intravenous (IV) dose and rate of magnesium for acute asthma exacerbation is not explicitly stated in the provided drug label. However, the label does provide a general guideline for the rate of IV injection, which should not exceed 150 mg/minute.

• The maximum dose for other conditions is mentioned, but not specifically for acute asthma exacerbation.
• Key considerations for dosage adjustment include individual requirements and response, as well as discontinuation of administration once the desired effect is obtained 2.

From the Research

Recommended IV Dose and Rate of Magnesium for Acute Asthma Exacerbation

• The recommended intravenous (IV) dose of magnesium sulfate for acute asthma exacerbation is typically a single bolus dose of 1.2 g or 2 g 3.
• The IV dose is usually administered over 15 to 30 minutes 3.
• The use of IV magnesium sulfate is indicated for patients with severe acute asthma who do not respond to initial treatment with a bronchodilator agent and systemic corticosteroids 4.
• The evidence favors the use of intravenous magnesium sulfate in selected cases, particularly in severe exacerbations 5.

Administration and Efficacy

• IV magnesium sulfate has been shown to reduce hospital admissions and improve lung function in adults with acute asthma who have not responded sufficiently to oxygen, nebulised short-acting beta2-agonists and IV corticosteroids 3.
• The administration of IV magnesium sulfate can provide additional bronchodilation when given in conjunction with standard bronchodilating agents and corticosteroids 6.
• The use of IV magnesium sulfate is safe and beneficial in patients who present with severe acute asthma, with few reported adverse effects 6, 4.

Specific Patient Populations

• In children with acute asthma, IV magnesium sulfate is effective and safe, although its use in the emergency room is still limited 4.
• The use of IV magnesium sulfate in adults with acute asthma has been shown to reduce hospital admissions and improve lung function, with high-quality evidence supporting its use in this population 3.