Clinical aspects of medication overuse headaches.

Medication overuse headache (MOH) is a subset of chronic daily headache, occurring from overuse of 1 or more classes of migraine abortive medication. Acetaminophen, combination analgesics (caffeine combinations), opioids, barbiturates (butalbital), non-steroidal anti-inflammatory drugs, and triptans are the main classes of drugs implicated in the genesis of MOH. Migraine seems to be the most common diagnosis leading to MOH. The development of MOH is associated with both frequency of use of medication and behavioral predispositions. MOH is not a unitary concept. The distinction between simple (type 1) vs complex (type 2) forms is based on both the class of overused medication and behavioral factors, including psychopathology and psychological drug dependence. MOH is a challenging disorder causing decline in the quality of life and causing physical symptoms, such as daily and incapacitating headaches, insomnia, and non-restorative sleep, as well as psychological distress and reduced functioning. MOH is associated with biochemical, structural, and functional brain changes. Relapse after detoxification is a challenge, but can be addressed if the patient is followed over a prolonged period of time with a combination of prophylactic pharmacotherapy, use of abortive medication with minimal risk of MOH, withholding previously overused medication, and providing psychological (cognitive-behavioral) therapy.