CRD Summary: This review evaluated the effectiveness of parenteral corticosteroids for acute migraine headache in adults. The authors concluded that single-dose parenteral dexamethasone, when added to standard abortive treatment for migraine, is associated with a 26% relative reduction in headache recurrence within 72 hours, though not associated with initial headache pain reduction. These conclusions follow from the evidence presented in a well-conducted review.

CRD Commentary: This was a well-conducted review of the evidence on the effectiveness of parenteral corticosteroids for the relief of acute migraine headache. The authors reported a well-defined search question that was supported by appropriate inclusion criteria. Attempts were made to identify all the relevant evidence, both published and unpublished, in any language, from a variety of electronic and other sources. Two reviewers independently selected studies for inclusion and extracted relevant data, though it is not clear if similar safeguards against error and bias were taken at the validity assessment stage. The validity of the selected studies was assessed using a validated scale, and the studies were synthesised using appropriate statistical methods, taking into account the degree of statistical heterogeneity. Given the evidence presented, the authors' conclusions appear appropriate.