Department of Family, Community and Preventive Medicine, University of Arizona College of Medicine, Phoenix, and St. Joseph’s Hospital Family Medicine Residency at Creighton University Arizona Health Education Alliance, Phoenix Allison.Crain@dignityhealth.org
The author reported no potential conflict of interest relevant to this article.
The prevalence of MOH in the general population is 2%.7,14,15 A population-based study showed that the rate of progression from episodic headache (< 15 d/mo) to chronic headache (≥ 15 d/mo) in the general population is 2.5% per year16; however, progression to chronic headache is 14% per year in patients with medication overuse. One-third of the general population with chronic migraine overuses symptomatic medication; in US headache clinics, roughly one-half of patients with chronic headache overuse acute medication.6
Definitions and diagnosis
MOH is a secondary headache diagnosis in the third edition of the International Classification of Headache Disorders (ICHD-3) (TABLE 1),17 which lists diagnostic criteria for recognized headache disorders.
Terminology.MOH has also been called rebound headache, drug-induced headache, and transformed migraine, but these terms are outdated and are not formal diagnoses. Patients sometimes refer to substance-withdrawal headaches (not discussed in this article) as rebound headaches, so clarity is important when discussing headache with patients: namely, that MOH is an exacerbation of an existing headache condition caused by overuse of abortive headache medications, including analgesics, combination analgesics, triptans, barbiturates, and opioids.
The time it takes to develop medication overuse headache is shortest with triptans, followed by ergots, then analgesics.
MOH was recognized in the early 1950s and fully differentiated as a diagnosis in 2005 in the second edition of the ICHD. The disorder is subcategorized by offending abortive agent (TABLE 217) because the frequency of analgesic use required to develop MOH differs by agent.
Risk factors for MOH and chronification of a primary headache disorder. There are several risk factors for developing MOH, and others that contribute to increasing headache frequency in general (TABLE 35,14,18-23). Some risk factors are common to each. All are important to address because some are modifiable.
