What is the role of magnesium in managing migraines?

Magnesium in Migraine Management

Oral magnesium supplementation is recommended for the prevention of migraine headaches with a dosage of 400-600mg daily. 1, 2

Evidence for Magnesium in Migraine Prevention

The 2024 U.S. Department of Veterans Affairs and Department of Defense Clinical Practice Guideline provides a "weak for" recommendation for oral magnesium in migraine prevention 2. This recommendation is supported by multiple studies demonstrating magnesium's efficacy in reducing migraine frequency and severity.

Key points about magnesium's role in migraine management:

• Magnesium deficiency may contribute to migraine pathogenesis through multiple mechanisms:

  • Promoting cortical spreading depression
  • Altering neurotransmitter release
  • Causing hyperaggregation of platelets
  • Affecting serotonin receptor function 3, 4

• Magnesium deficiency appears to be more prevalent in migraine sufferers than in healthy controls 4

• The recommended dosage for prevention is 400-600mg daily 1

Clinical Evidence

A double-blind, randomized, placebo-controlled study found that 600mg/day of oral magnesium citrate supplementation for 3 months significantly:

• Decreased migraine attack frequency
• Reduced attack severity
• Lowered P1 amplitude in visual evoked potential examination
• Increased cortical blood flow in several brain regions 5

These effects were statistically significant compared to placebo, suggesting both vascular and neurogenic mechanisms of action.

Acute Treatment with Magnesium

For acute migraine attacks, intravenous magnesium sulfate (1g) has shown efficacy:

• One study reported complete pain relief in 86.6% of patients
• All patients experienced resolution of accompanying symptoms
• This was significantly superior to placebo 6

However, current guidelines focus primarily on oral magnesium for prevention rather than IV magnesium for acute treatment.

Implementation in Clinical Practice

When considering magnesium for migraine prevention:

1. Patient selection: Consider magnesium particularly for patients with:

   • Frequent migraine attacks (≥2 per month)
   • Desire for non-pharmaceutical options
   • Contraindications to other preventive medications

2. Dosing: Start with 400-600mg daily of oral magnesium 1

3. Formulation: Magnesium citrate or glycinate may be better absorbed than magnesium oxide

4. Duration: Allow 6-8 weeks for full effect assessment, with a target goal of 50% reduction in headache frequency 1

5. Monitoring: Watch for gastrointestinal side effects (diarrhea, abdominal cramping)

Limitations and Considerations

• Blood tests may not accurately reflect magnesium status since <2% is in the measurable extracellular space 4

• Magnesium can be used alongside other preventive treatments as part of a comprehensive approach

• Common side effects are generally mild and include gastrointestinal symptoms 6

• Magnesium should be used with caution in patients with renal impairment

Placement in Treatment Algorithm

Magnesium can be considered:

• As a first-line preventive option for patients preferring non-pharmaceutical approaches
• As an adjunctive therapy alongside other preventive medications
• In patients with contraindications to standard preventive medications

While the evidence supports magnesium's efficacy, it's important to note that the recommendation is "weak for" rather than "strong for," indicating moderate rather than high-quality evidence 2.