Chronic migraine (CM) best characterizes those patients with a history of migraine who experience headache more than half the time. This condition was previously called Transformed Migraine (TM). However, transformation requires that the sufferer recall precisely how their headaches have changed over time. This new description will provide a usable definition for medical research studies of new treatment options.
The following criteria for CM have been put forth by the International Headache Society:
- Headache, of either tension-type and/or migraine quality, occurs on ≥15 days per month for at least 3 months.
- On ≥8 days per month the patient experiences the pain and associated symptoms of migraine without aura and/or treats and experiences relief before the expected development of symptoms
- No medication overuse
Initial treatment options for CM should focus on control of one or more factors shown to contribute to headache occurrence. These triggers would include changes in diet, sleep, exercise, and psychological well-being, in addition to many other potential influencing factors. Caffeine, alcohol, tobacco, and use of select over-the-counter (OTC) and prescription medications should be minimized due to their potential for increasing headache risk. Treatment options can further be subdivided into acute and preventive pharmacotherapy. Some of the acute treatment options include simple analgesics, non-steroidal anti-inflammatory drugs (NSAIDS), triptans, and ergotamines. Use of these agents should be limited to 2 or fewer days per week to minimize risk for rebound headache that would complicate treatment and possibly require detoxification. Preventive pharmacotherapy focuses on several different classes of medications, including antidepressants, anticonvulsants, beta-blockers, or calcium channel blockers. Onabotulinum toxin A (Botox) is actually the only medication approved by the FDA specifically for chronic migraine. Patients starting new preventive therapy should keep in mind that it may take one to two months for full treatment effects to take place.