The use of intravenous magnesium sulphate for acute migraine: meta-analysis of randomized controlled trials.

OBJECTIVE: The objective of this study was to assess the efficacy and tolerability of intravenous magnesium for the treatment of acute migraine in adults.

SELECTION CRITERIA: Double-blind, randomized controlled trials of intravenous magnesium for acute migraine in adults.

DATA SOURCES: Cochrane Central Register of Controlled Trials, Medline, EMBASE, CINAHL, National Research Register Archive, ACP Journal Club, the US Government's Clinical Trial Database, Conference Proceedings, and other sources.

RESULTS: Overall, 1203 abstracts were reviewed and five randomized controlled trials totalling 295 patients were eligible for the meta-analyses. The percentage of patients who experienced relief from headache 30 min following treatment was 7% lower in the magnesium groups compared with the controls [pooled risk difference=-0.07, 95% confidence interval (CI)=-0.23 to 0.09]. The percentage of patients who experienced side-effects or adverse events was greater in the magnesium groups compared with controls by 37% (pooled risk difference=0.370, 95% CI=0.06-0.68). The percentage of patients who needed rescue analgesic medications was slightly lower in the control groups, but this was not significant (pooled risk difference=-0.021, 95% CI=-0.16 to 0.12).

CONCLUSION: The meta-analyses have failed to demonstrate a beneficial effect of intravenous magnesium in terms of reduction in pain relief in acute migraine in adults, showed no benefit in terms of the need for rescue medication and in fact have shown that patients treated with magnesium were significantly more likely to report side-effects/adverse events.