Medication Overuse Headaches (MOH)

Medication overuse headache (MOH), previously called rebound headache, drug-induced headache, and medication misuse headache, is a subset of chronic daily headache (CDH), occurring on 15 days or more per month, 4 or more hours per day, for 3 or more months with the added feature of overuse of at least 1 class of abortive drug. In clinical practice, the common scenario is a patient with episodic migraine (EM) that transforms to chronic migraine (CM) in the setting of overusing 1 or more classes of abortive drugs. The main classes of drugs that cause MOH are: opioids, butalbital-containing mixed analgesics, triptans, simple analgesics, except for plain aspirin, and perhaps NSAIDs. There is an increase in frequency and intensity of headache attacks and enhanced sensitivity to stimuli that would trigger these attacks.

MOH prevalence is estimated in about 1-2% of the general population and is overwhelmingly more prevalent in women than in men. In specialized headache centers, the prevalence of MOH can be as high as 70% among referred patients, and if its high socioeconomic impact is taken into account (work absenteeism, recurrent emergency room visits, hospital admissions, and unnecessary diagnostic tests), MOH is likely to be one of the most if not the most costly neurological disorder known.

The general quality of life of MOH patients is worse than patients with episodic headaches

The most frequent headache diagnoses at onset are the following: migraine in 65%, tension-type headaches in 27%, and mixed or other headaches in 8%.

It also appears that migraine starts earlier in the life of patients with MOH than in those with EM. Cluster headache with coexisting migraine disorder can also be susceptible to developing MOH, and triptans along with opioids are the most common offending drugs.

The treatment of MOH consists of discontinuation of the offending drug(s), acute treatment of the withdrawal symptoms and escalating pain, establishing a preventive treatment when necessary, and the implementation of educational and behavioral programs to prevent recidivism.

In most patients MOH can be treated in the outpatient setting but for the most difficult cases including those with opioid or butalbital overuse, or in patients with serious medical or behavioral disturbances, effective treatment requires a multidisciplinary, comprehensive headache program, either day-hospital with infusion or inpatient hospital setting.