Melatonin responsive hemicrania continua.

Hemicrania continua is one of the indomethacin-responsive headache syndromes. There are very few effective alternative therapies for hemicrania continua, thus patients may require daily indomethacin for years. The risks of long-term indomethacin include gastrointestinal and renal dysfunction. Melatonin is a pineal hormone with a chemical structure very similar to indomethacin. Recently, melatonin was shown to be effective for primary stabbing headache, another indomethacin-responsive syndrome. Three cases of melatonin responsive hemicrania continua are now reported.