Triptan nonresponders: Do they exist and who are they?

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. Conclusion: 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.