From the Guidelines
Intravenous magnesium sulfate can be used for acute migraine attacks at a dose of 1-2 grams administered over 15-30 minutes, as supported by the most recent evidence 1. The typical regimen is 1 gram of magnesium sulfate diluted in 100 mL of normal saline. This treatment may be particularly effective for patients with migraine with aura, menstrual migraine, or those with documented magnesium deficiency.
- Magnesium works by blocking N-methyl-D-aspartate (NMDA) receptors, stabilizing neuronal membranes, and reducing cerebral vasospasm, all of which can help alleviate migraine symptoms.
- Common side effects include flushing, burning sensation at the IV site, hypotension, and nausea.
- Patients should be monitored for signs of magnesium toxicity such as muscle weakness, respiratory depression, and cardiac abnormalities, especially those with renal impairment.
- IV magnesium should be administered in a medical setting where vital signs can be monitored. It's generally considered a second-line treatment when standard abortive medications have failed or are contraindicated, as suggested by previous studies 1.
From the Research
IV Magnesium Dose for Migraine Attack
- The efficacy of intravenous magnesium sulfate in the treatment of acute migraine attacks has been studied, with one study 2 using a dose of 1 g intravenous magnesium sulfate given over 15 minutes.
- This study found that all patients in the treatment group responded to treatment with magnesium sulfate, with the pain disappearing in 13 patients (86.6%) and diminishing in 2 patients (13.4%).
- Another study 3 used a dose of 2 g of intravenous magnesium sulfate, but found that the addition of magnesium to metoclopramide may attenuate the effectiveness of metoclopramide in relieving migraine.
- A meta-analysis 4 of randomized controlled trials found that the percentage of patients who experienced relief from headache 30 min following treatment was 7% lower in the magnesium groups compared with the controls.
- However, a more recent study 5 found that there was no significant difference in pain relief between patients treated with intravenous magnesium and those treated with prochlorperazine or metoclopramide.
Dosage and Administration
- The dose of intravenous magnesium sulfate used in the studies varied, with one study 2 using a dose of 1 g and another study 3 using a dose of 2 g.
- The administration of magnesium sulfate also varied, with one study 2 giving the dose over 15 minutes and another study 3 giving the dose at 15-minute intervals for a maximum of 3 doses or until pain relief occurred.
Efficacy and Safety
- The efficacy of intravenous magnesium sulfate in the treatment of acute migraine attacks is still unclear, with some studies 2 finding it to be effective and others 3, 4 finding it to be less effective or even countertherapeutic.
- The safety of intravenous magnesium sulfate has been evaluated, with one study 2 finding that 26 patients (86.6%) had mild side effects which did not necessitate discontinuing treatment during magnesium sulfate administration.
- Another study 5 found that the reported adverse effects were dizziness, anxiety, and akathisia, but there were no statistically significant differences in adverse effects between the treatment groups.