Evidence-based understanding of medication-overuse headache: clinical implications.

This article discusses the problem of medication-overuse headache from a variety of perspectives, based on the best available evidence. This presentation clarifies the definition of the disorder, distinguishing it from alternative terminology, and describes its epidemiology, natural history, and clinical course. Antimigraine medications are believed to differ in their relative liability to contribute to the development of medication-overuse headache. Patients most at risk of developing medication-overuse headache need to be identified so that appropriate preventive measures can be initiated.