Effect of Medications on Pain Perception and Its Central Modulation in Episodic and Chronic Migraine Patients (P04.245)

Abstract

Objective: Migraine overuse headache (MOH) manifests itself as an increase in the frequency of migraine attacks associated with repeated consumption of acute migraine treatment. The pathophysiology and role of medication in MOH are poorly understood. Background We studied pain perception and diffuse noxious inhibitory controls (DNIC) in healthy volunteers, episodic migraine (EM) and MOH patients before and 3 weeks after withdrawal of medications. Design/Methods: A total of 32 female subjects were included in a 2 session-protocol. To assess DNIC, blocs of 4 thermal test stimuli (Nd:YAP laser stimulator, diameter 4 mm; duration 5 ms) were delivered at 0.2 Hz on the back of the left hand, repeated every 25 sec for 30 min, at an intensity producing a moderate pain (3-6 on 0-10 VAS). Between the 10th and 20th min, the contralateral foot was immersed into a water bath (conditioning stimulus) at neutral (30°C) or noxious cold (8°C; DNIC session) temperature, randomly on different days. DNIC was assessed as the ratio between the areas under the curve in cold and warm conditions. Pain summation to repetitive thermal stimuli was assessed on responses to trains 1-15.° Results: EM patients had lower pain thresholds and enhanced pain perception to repetitive painful stimuli. EM patients also demonstrated smaller DNIC (11.5±7.2%, n=12) than both healthy volunteers (30.4±9.5%, n=9) and MOH patients (28.5±11.0%, n=11). Three week after medication withdrawal, MOH patients exhibited a significant reduction in the number of headache days per month (from 29.4±0.6 to 10.1±3.2, P Conclusions: These data suggest that episodic migraine is associated with high pain ratings for painful stimuli and impaired descending pain inhibition. Interestingly, though medication overuse worsens migraine, it is not associated with such impairment. Thus, medication overuse might reverse migraine-induced impairment in descending pain inhibition. Supported by: CHU de Clermont Ferrand. Disclosure: Dr. Guy Renouil has nothing to disclose. Dr. Clavelou has received personal compensation for activities with Schering-Plough Corporation, Biogen Idec, Serono, Inc., and Sanofi-Aventis Pharmaceuticals, Inc. as a speaker. Dr. Dallel has nothing to disclose.