Medication overuse headache is a recurring headache affecting individuals who regularly take analgesic medications for a preexisting headache syndrome. Other terms commonly used for this condition include rebound headache and medication-misuse headache. Drug-induced headaches are similar but can occur with use of multiple different medications rather than just with analgesics.

Medication overuse headache is defined as a headache occurring 15 or more days a month, when headache medicine has been overused for 3 or more months (frequent and/or excessive dosage). Medication overuse headaches may be different or significantly worse than the patient's baseline headaches.

Any acute headache treatment can predispose patients to medication overuse headaches if taken excessively. Over-the-counter analgesics are the most frequently overused medications. Using NSAIDs for 15 or more days per month can predispose to medication overuse headaches. Triptans and ergotamines can lead to medication overuse headaches when taken 10 or more days per month. Use of opioids or barbiturates on 5-8 days per month can lead to a risk of medication overuse headaches. 

Medication overuse headaches are common, affecting about 1%-2% of the general population. Among patients with chronic primary headache disorders, about 25%-50% will meet diagnostic criteria for medication overuse headaches at some point. Medication overuse headaches are more common in females, with a female to male ratio of 3.5-1.

Medication overuse headaches can be classified as simple or complex. Patients overusing opioids or barbiturate medications are generally classified as having complex medication overuse headaches, as are patients overusing multiple different classes of acute headache treatments. Complex medication overuse headaches are also diagnosed in patients with prior failed attempts to withdraw from overused medications, concurrent mental illnesses, and other complex medical comorbidities.

Related topics: Migraine headache, Tension-type headache