Intravenous magnesium knocks out acute migraines - Literature Review & Commentary

Townsend Letter for Doctors and Patients, Nov, 2002 by Alan R. Gaby

Thirty patients with moderate or severe migraine attacks were studied. The first 15 patients received, in single-blind fashion, 1 g of magnesium sulfate (Mg) intravenously over 15 minutes, and the next 15 patients received placebo (10 ml of 0.9% sodium chloride intravenously). Patients in the latter group who did not experience relief of pain, nausea and vomiting after 30 minutes were then treated with Mg. Immediately after treatment and at 30 minutes and two hours, 13 of 15 patients (86.6%) in the Mg group were pain-free, and the remaining two patients reported a reduction in pain severity. At all three time periods, accompanying symptoms (such as nausea, vomiting, photophobia, and irritability) had disappeared in each of the 14 patients who experienced them. None of the patients given Mg had a recurrence of pain within 24 hours. lathe placebo group, no patient became pain-free (p < 0.001 for group difference) and only one (6.7%) experienced a reduction in pain. Accompanying symptoms disappeared in three pat ients (20%) 30 minutes after placebo administration (p < 0.0001 for group difference). When patients in the placebo group were given Mg, the response was similar to that in the Mg group. Mild side effects (such as a burning sensation in the face and neck, flushing, and/or a 5-10 mm Hg drop in systolic blood pressure) occurred in 86.6% of the patients given Mg. However, none of these side effects were serious, and no patient had to discontinue the treatment.

Comment: The results of this study are consistent with those of a previous report (Clin Sci 1995;89:633-6) demonstrating that intravenous magnesium can rapidly abort an acute migraine. Double-blind studies would be difficult, if not impossible, to perform, because intravenous magnesium produces obvious side effects (described above) in most patients. However, because of the dramatic benefits reported, this treatment deserves consideration as first-line therapy for migraine attacks. Most doctors charge $30-50 to administer intravenous magnesium (the magnesium itself costs only a few dollars); this compares favorably with the $50 or so for a single dose of self-administered subcutaneous sumatriptan (Imitrex[R]). However, intravenous magnesium is much safer than Imitrex, which has been linked on rare occasions with myocardial infarction, hypertensive crisis, and death.

Demirkaya S, et al. Efficacy of intravenous magnesium sulfate in the treatment of acute migraine attacks. Headache 2001;47:171-177.