From drug-induced headache to medication overuse headache. A short epidemiological review, with a focus on Latin American countries.

Medication overuse headache (MOH) is a daily or almost-daily type of headache that results from the chronicization, usually migraine or tension-type headache, as a consequence of the progressive increase of intake of symptomatic drugs. MOH is now the third most frequent type of headache and affects a percentage of 1-1.4% of the general population. The currently available data on the impact of chronic headache associated with analgesic overuse in specialist headache centres confirm, beyond doubt, the existence of a serious health problem. Limited amount of data exists on the burden and impact of MOH in Latin American Countries. In this review, we summarise the reliable information from the literature on the epidemiological impact of MOH.