Some migraine patients fall into a trap by overusing the medications they take when they get their headaches, ending in a downward spiral of daily or near-daily headaches for which their medications become less and less effective.
This condition, called medication overuse headache, makes for a poor quality of life. It is often associated with nonrestorative sleep, neck pain, and vasomotor instability. Comorbid depression and anxiety are common and may complicate treatment. (Depression and anxiety, however, do not cause daily headaches.) Patients can also suffer from the physiologic and psychological consequences of the overused medications.
Fortunately, we can break the cycle.1,2 Treatment involves completely weaning the patient from the overused medications and educating her or him to follow a new regimen of prophylaxis and acute treatment with clear limits on frequency of use. Nondrug treatments such as relaxation therapy, biofeedback, and cognitive behavioral therapy can be useful adjuncts.
CROSSING THE LINE: 15 HEADACHE DAYS A MONTH
Chronic daily headache
We define chronic daily headache as occurring on at least 15 days per month for at least 3 months in a row and lasting at least 4 hours if untreated.
Most patients start with episodic migraine, and many of them remember the period of transformation. Crossing the 15-day-per-month threshold changes the clinical presentation, prognosis, and treatment, all for the worse.
In a large population-based study,3 2.5% of patients who began with episodic migraine (headaches on fewer than 15 days per month) had “transformed migraine” (headaches on 15 or more days per month) 1 year later. The prevalence of chronic daily headache is almost 5% of the general population and may account for up to 70% of the initial diagnoses seen in headache centers.
The closer a patient is to having 15 headaches per month, the more likely she or he will cross the line.4,5 Katsarava and colleagues5 followed patients for 1 year in a neurology clinic in Germany and found that those starting the year with 6 to 9 headache days per month were 6.2 times more likely to develop chronic daily headache in the next year than those who began the year with 0 to 4 per month—and those starting with 10 to 14 headaches per month were 20 times more likely.
Medication overuse headache
Medication overuse headache is a subset of chronic daily headache, also occurring on 15 or more days per month but with the added criterion of medication overuse, ie, regular overuse for more than 3 months of at least one acute treatment drug:
- Ergotamine, triptans, opioids, or combination analgesic medications on 10 or more days per month on a regular basis for more than 3 months, or
- Simple analgesics or any combination of ergotamine, triptans, analgesics, or opioids on 15 or more days per month on a regular basis for more than 3 months without overuse of any single class alone.
Another criterion is that the patient’s headaches must worsen in some way (usually frequency) as the use of acute medications becomes more frequent.6,7
Medication overuse headache is the most common form of secondary chronic daily headache seen in headache practice,8–10 and probably accounts for about half of cases of chronic daily headache.11–13
Different terminology confuses the issue
Many terms have been used to describe medication overuse headache in the past, such as analgesic-rebound headache (or just rebound headache), transformed migraine with medication overuse, and even chronic migraine. The lack of uniformity in terminology makes for confusion in the literature and difficulty in communicating with patients and colleagues. Some authors mean medication overuse headache when they say chronic daily headache.
Complicating this diagnostic confusion is a debate as to whether chronic daily headache in general should be treated as a primary or secondary headache disorder. Some European headache specialists insist on a strict division between primary and secondary daily headaches, and medication overuse headache is one of the latter. Many American specialists believe that chronic daily headache is a collective description or phenotype rather than a diagnostic category, and that it is usually associated with and exacerbated by medication overuse.14,15 The International Classification of Headache Disorders uses the term “chronic migraine” for primary daily headache, and “medication overuse headache” for secondary daily headache or rebound.
Many American specialists approach the disorder clinically, treating chronic daily headache in the same way regardless of whether there is medication overuse. They cite randomized controlled trials of topiramate (Topamax) and onabotulinum toxin type A (Botox) that reported comparable benefit with these medications in patients with chronic daily headache with or without medication overuse.16–18
MORE IS LESS: THE PARADOX OF TREATING ACUTE HEADACHE
The clinical paradox and dilemma of treating acute episodic migraine is that more is less: the more days of acute treatment, the less well the migraines are controlled. And thus, the patient is likely to veer out of control.3
The compassion that motivates us to prescribe medications for acute episodic migraine must be tempered by the realization that too much of a good thing will result in its malignant transformation to medication overuse headache. Once this develops, preventive and migrainespecific acute medications are less effective, and patients need far more complex interventions.
Complicating the dilemma, acute migraine-specific medications such as triptans and dihydroergotamine (Migranal) work better when taken early in migraine attacks, before central sensitization and allodynia develop with attendant photophonophobia and sensitivity to other stimuli. On the other hand, overuse will lead to medication overuse headache.