CRD Summary: The authors concluded that dexamethasone was moderately effective at preventing headache recurrence when used in the emergency department as an addition to standard treatment of acute migraine headache. Side effects were mild and transient. The conclusions appear reliable, although (as the authors noted) the small number and size of the primary studies necessitates a degree of caution in interpretation.

CRD Commentary: The objectives and inclusion criteria of the review were clear. Relevant sources were searched without restriction by language or publication status. Steps were taken to minimise bias and error by having more than one reviewer independently conduct study selection, validity assessment and data extraction. Appropriate statistical methods were used to combine studies and to assess for heterogeneity and publication bias. Potential biases and sources of confounding were well addressed in the text. Although the trials were small, they were of acceptable quality and their results were consistent. The review was well conducted and the authors’ conclusions appear reliable, although (as they noted) the small number and size of the primary studies necessitates a degree of caution in interpretation.