How effective is melatonin as a preventive treatment for hemicrania continua? A clinic-based study

Objective To assess the efficacy of melatonin as a preventive therapy for hemicrania continua in a larger population of patients than has previously been studied. Background Hemicrania continua is defined by its sensitivity to indomethacin. Rarely can patients be fully tapered off indomethacin without headache recurrence; thus, the risks associated with chronic indomethacin usage are substantial for these individuals. Melatonin, a pineal hormone with a similar chemical structure to indomethacin, has shown efficacy as a preventive agent for hemicrania continua in isolated case reports. Melatonin would be a preferential alternative prophylactic treatment to indomethacin because of its minimal side effect profile. How truly effective melatonin is as a preventive for hemicrania continua is unknown at present and needs further study. Methods Retrospective analysis of all International Classification of Headache Disorders-3 beta diagnosed hemicrania continua patients treated with both indomethacin and melatonin at the Geisinger Headache Center from July 2011 to January 2014. Results Eleven patients were treated (9 women, 2 men). Two patients became pain free on melatonin, while partial relief was noted in 3 other patients; thus, they were able to lower their dose of indomethacin but could not achieve pain freedom with melatonin alone. Six patients had no response. Melatonin dosing needed for response ranged from 3 to 30 mg. In the partial relief responders, indomethacin dosing decreased by 50% to 75%. Conclusion From this single clinic investigation, only a small percent of subjects with hemicrania continua (less than 20%) will achieve pain freedom on melatonin, thus clearly not matching the effectiveness of indomethacin. However, the addition of melatonin to indomethacin may allow around 45% of patients to have complete or partial relief of their headache with the subsequent ability to reduce or eliminate their indomethacin dosage, which may lead to a decrease in medical morbidity over time secondary to less exposure to indomethacin.