Recurrence was first recognised as a clinical problem in 1989 with the advent of sumatriptan. The history of recurrence in early sumatriptan randomised clinical trials is described. Recurrence has been ascribed to patient-dependent factors but experience with ergot alkaloids suggested that recurrence can also be treatment-dependent. Possible mechanisms for recurrence are discussed.
Journal of Headache and Pain, 2009, Vol 10, Issue 5, p. 311-5