Negro, A Chronic migraine: current concepts and ongoing treatments. [electronic resource] - European review for medical and pharmacological sciences Dec 2011 - 1401-20 p. digital Publication Type: Journal Article; Review ISSN: 1128-3602 Subjects--Topical Terms: AdultAnalgesics--administration & dosageBotulinum Toxins, Type A--adverse effectsChronic DiseaseHeadache Disorders, Secondary--diagnosisHumansMigraine Disorders--drug therapyRisk FactorsSubstance Withdrawal Syndrome