Probable medication-overuse headache: the effect of a 2-month drug-free period.

OBJECTIVE: To describe the emerging profile of headache frequency following a 2-month drug-free period in patients with medication overuse.

METHODS: All patients treated and discharged from Danish Headache Center in 2002 and 2003 had prospectively filled out a diagnostic headache diary on a daily basis. For patients with probable medication-overuse headache (MOH), the authors determined headache frequencies before and after medication withdrawal from these prospective recordings.

RESULTS: Among 1,326 patients, 337 had probable MOH. Two hundred sixteen patients who stayed medication-free for 2 months were eligible. Overall, 45% of the patients improved, 48% had no change, and 7% had more headaches. Median age was 48 years, and male/female ratio 1:2.7. The relative reduction in headache frequency varied considerably with a 67% median reduction in migraine, 0% in tension-type headache (TTH), and 37% in patients with both migraine and TTH (MT). Comparing the diagnostic groups, the relative reduction in frequency differed between migraine and TTH (p < 0.001) and between MT and TTH (p < 0.01). Triptan/ergot overusers improved the most (p < 0.0001). The difference between MT and TTH remained significant when triptan/ergot overuse was controlled (p < 0.05).

CONCLUSION: These data demonstrate the benefit of withdrawal in already established medication overuse and support the existence of medication-overuse headache as a clinical entity.