title: Triptan nonresponders: do they exist and who are they?
abstract: BACKGROUND
  Triptans represent the best treatment option for most migraine attacks, although this is not as well studied as it might be in controlled trials. Their efficacy and tolerability vary, both between agents, and from patient to patient, with about 30%-40% of patients not responding adequately to therapy. As yet unexplained, the failure of one triptan does not predict failure with another, and therefore triptan nonresponders cannot be defined as individuals who have failed a single triptan. Five clinical studies provide evidence that switching from a triptan that is ineffective to a second one can result in effective treatment in a proportion of patients. Systematic studies investigating whether there are patients who do not respond to all triptans in all formulations are lacking.
  
  
  METHODS
  Here we discuss the importance of identifying triptan nonresponders, the literature supporting their existence, and the issues to be resolved to design trials to investigate this.
  
  
  CONCLUSIONS
  So far, no scientific data about the presence of a triptan nonresponder population are available. We propose a pragmatic study design to assess the existence of this subpopulation, recognizing the complexity of the question and the likelihood that more than one issue is at play in nonresponders.
authors.affiliation: Headache Science Center, C. Mondino National Institute of Neurology Foundation, IRCCS, Pavia, Italy. michele.viana@mondino.it
authors.forename: Michele
authors.initials: M
authors.lastname: Viana
authors.forename: Armando A
authors.initials: AA
authors.lastname: Genazzani
authors.forename: Salvatore
authors.initials: S
authors.lastname: Terrazzino
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Nappi
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Goadsby
mesh_terms: D000700:Analgesics / Q000008:administration & dosage*; D004351:Drug Resistance; D006801:Humans; D008881:Migraine Disorders / Q000188:drug therapy*; D014363:Tryptamines / Q000008:administration & dosage*
chemical_list: D000700:Analgesics; D014363:Tryptamines
keywords: Triptan; migraine; nonresponder; population; predictor; responder