Medication-Overuse Headache

Excerpt

Medication-overuse headache (MOH) is a common neurologic disorder with enormous disability and suffering and plays a significant role in the transformation from episodic to chronic headache disorders. Multiple terms have been used to describe MOH, such as analgesic rebound headache, drug-induced headache, or medication-misuse headache. Patients with established primary headache disorders like migraine or tension-type headaches overuse medication for their acute headaches and inadvertently increase the frequency and intensity of their headaches. In this manner, a vicious cycle of further drug consumption and increased headache frequency develops, transforming the treatment for their headache to the actual cause of their disease (MOH). Patients prone to headaches who take analgesics for other conditions can also develop MOH.

Recognition of MOH was as early as in the 1930s when physicians observed prolongation of headaches associated with ergotamine-overuse. In the 1970s and 1980s, physicians observed its association with analgesics such as barbiturates, codeine, and combination analgesics as well and also noticed a reduction in headache frequency with stopping drugs. For a short time, it was referred to as transformed or evolutive migraine. The first edition of the International Classification of Headache Disorders (ICHD) in 1988 first defined the disorder calling it a drug-induced headache that was a “headache induced by chronic substance use or exposure.” MOH was first introduced in the second edition of ICHD (2004) with multiple subtypes dependent on offending medicine, such as ergotamines, triptans, opioids, etc.