[Hypnic headache as a primary short-lasting night headache: a report of two cases].

Hypnic headache is a rare type of primary short-lasting headache related to sleep. The pathogenesis of hypnic headache still remains unknown, but it may be a chronobiological disturbance or a response to a pineal circadian irregularity in which melatonin may play a role in resynchronizing biological rhythms to lifestyle. It is a moderate headache that appears during sleep with almost an alarm clock regularity and lasts up to 60 minutes. The headache is boring, unilateral or with diffuse location. Lithium carbonate and flunarizine show the best efficacy, caffeine and melatonin may also be useful. The author describes two cases of hypnic headache, which were effectively treated. A 45-year-old woman was treated with flunarizine and melatonin and a 65-year-old man was treated with flunarizine. The efficacy of flunarizine may be associated with the activation of D2 receptor and the added treatment with melatonin may hasten the good effect similar to that seen in our patient.