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Sumatriptan and daily headache.

Frequent use of ergotamine and simple analgesics is well recognised as a cause of chronic headache syndromes induced by drugs or drug withdrawal. Sumatriptan, a new and highly effective antimigraine drug, seemed not to produce this unpleasant side effect, as shown by long term studies.' Nevertheless, eight cases of sumatriptan misuse and daily chronic headache have been reported recently.23 Another 10 similar cases have been published in abstract form.4-6 The discrepancy between drug trials and clinical evidence may be due to the type of patients considered. In fact, eight of the 18 patients who used sumatriptan daily switched from misuse of analgesics or ergotamine to misuse of sumatriptan, 10 (nine of whom were migraineurs with a previous history of analgesic overuse) developed sumatriptan induced daily headache de novo. This kind of patient is not usually included in drug trials but is often found in clinical practice. Sumatriptan has been reported to induce repeated recurrence of migraine attacks that respond to further doses of the drug.7 8 It may be possible that a similar mechanism occurs in drug induced migraine-like headache. In our opinion only one dose per week of sumatriptan should be prescribed