title: Treatment of Chronic Migraine with OnabotulinumtoxinA: Mode of Action, Efficacy and Safety.
abstract: BACKGROUND
  Chronic migraine is a common, highly disabling, underdiagnosed and undertreated entity of migraine. It affects 0.9%-2.2% of the general adult population. The present paper overviews the preclinical and clinical data regarding the therapeutic effect of onabotulinumtoxinA in chronic migraineurs.
  
  
  METHODS
  A literature search was conducted in the database of PubMed up to 20 May 2015 for articles related to the pathomechanism of chronic migraine, the mode of action, and the efficacy, safety and tolerability of onabotulinumtoxinA for the preventive treatment of chronic migraine.
  
  
  RESULTS
  The pathomechanism of chronic migraine has not been fully elucidated. The mode of action of onabotulinumtoxinA in the treatment of chronic migraine is suggested to be related to the inhibition of the release of calcitonin gene-related peptide and substance P in the trigeminovascular system. Randomized clinical trials demonstrated that long-term onabotulinumtoxinA fixed-site and fixed-dose (155-195 U) intramuscular injection therapy was effective and well tolerated for the prophylactic treatment of chronic migraine.
  
  
  CONCLUSIONS
  Chronic migraine is a highly devastating entity of migraine. Its exact pathomechanism is unrevealed. Two-third of chronic migraineurs do not receive proper preventive medication. Recent clinical studies revealed that onabotulinumtoxinA was an efficacious and safe treatment for chronic migraine.
authors.affiliation: Department of Neurology, University of Szeged, Semmelweis str. 6, Szeged H-6725, Hungary. szok.delia@med.u-szeged.hu.
authors.forename: Délia
authors.initials: D
authors.lastname: Szok
authors.affiliation: Department of Neurology, University of Szeged, Semmelweis str. 6, Szeged H-6725, Hungary. csati.anett@gmail.com.
authors.forename: Anett
authors.initials: A
authors.lastname: Csáti
authors.affiliation: MTA-SZTE Neuroscience Research Group, Szeged H-6725, Hungary. vecsei.laszlo@med.u-szeged.hu.
authors.forename: László
authors.initials: L
authors.lastname: Vécsei
authors.affiliation: Department of Neurology, University of Szeged, Semmelweis str. 6, Szeged H-6725, Hungary. tajti.janos@med.u-szeged.hu.
authors.forename: János
authors.initials: J
authors.lastname: Tajti
mesh_terms: D000700:Analgesics / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use*; D002908:Chronic Disease; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007273:Injections, Intramuscular; D008881:Migraine Disorders / Q000209:etiology / Q000517:prevention & control*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D000700:Analgesics; D019274:Botulinum Toxins, Type A
keywords: chronic migraine; efficacy; mode of action; onabotulinumtoxinA; pathomechanism; safety; tolerability; treatment