[Gordian knot: medication overuse headache].

Overuse of any kind of headache drugs may lead to the development of the medication overuse headache (MOH). Clinical features of MOH depend on the substance class that has been overused. Overuse of analgesics leads to a chronic tension-type like headache, the overuse of triptans to daily migraine-like headache or to the increase of migraine frequency. The delay between the drug overuse and onset of daily headache is shortest for triptans (1.7 years), longer for ergots (2.7 years) and longest for analgesics (4.8 years). Treatment includes withdrawal followed by structured acute therapy and initiation of specific prophylactic treatment for the underlying primary headache. The relapse rate after a successful withdrawal is about 30%. Predictors for relapse are tension-type headache and the overuse of analgesics in combination with codeine, caffeine or opioids.