Effects of Intravenous and Oral Magnesium on Reducing Migraine: A Meta-analysis of Randomized Controlled Trials.

BACKGROUND Migraine attack has been associated with magnesium deficiency. Previous studies investigating the effect of intravenous and oral magnesium on acute migraine attacks and the prevention of migraine have produced equivocal findings. OBJECTIVE To evaluate the effects of intravenous magnesium on acute migraine attacks and oral magnesium supplements on migraine prophylaxis. STUDY DESIGN A meta-analysis of randomized controlled trials (RCTs). Electronic databases, namely EMBASE, PubMed, the Wanfang Data Chinese Database, and the China Knowledge Resource Integrated Database were searched from inception to February 24, 2015. METHODS This review was conducted according to the guidelines of the PRISMA. Only RCTs evaluating the effects of intravenous or oral magnesium on migraine compared with a control group were included. RESULTS A total of 21 studies were included. Of which, 11 studies investigated the effects of intravenous magnesium on acute migraine (948 participants) and 10 examined the effects of oral magnesium on migraine prophylaxis (789 participants). Intravenous magnesium significantly relieved acute migraine within 15 - 45 minutes, 120 minutes, and 24 hours after the initial infusion (Odd ratios [ORs] = 0.23, 0.20, and 0.25, respectively). Oral magnesium significantly alleviated the frequency and intensity of migraine (ORs = 0.20 and 0.27). LIMITATIONS Some of the included studies did not adopt adequate randomization methods. CONCLUSIONS Intravenous magnesium reduces acute migraine attacks within 15 - 45 minutes, 120 minutes, and 24 hours after the initial infusion and oral magnesium alleviates the frequency and intensity of migraine. Intravenous and oral magnesium should be adapted as parts of multimodal approach to reduce migraine.