[Frequent episodic migraine and calcitonin gene-related peptide. Influence of treatment with topiramate and zonisamide on levels of the peptide].

INTRODUCTION

The pathophysiology of pain in migraine is related to the activation of the trigeminovascular system by releasing vasoactive neuropeptides, the most important of which is calcitonin gene-related peptide (CGRP), which causes a neurogenic inflammation in the leptomeningeal vessels.

AIM

To study whether CGRP is increased in frequent episodic migraine and whether preventive treatment with topiramate or zonisamide modifies its levels.

SUBJECTS AND METHODS

We studied 28 patients with episodic migraine with or without aura, in accordance with the International Headache Society criteria, with a frequency of 4-14 days/month. Plasma levels of CGRP were determined in all the patients during an interictal period (> 72 hours without pain). Patients were divided at random into two treatment groups, one with 50 mg/day of topiramate and the other with 50 mg/day of zonisamide, for three months. At the end of the active period the CGRP level was analysed again. The control group consisted of nine healthy subjects.

RESULTS

CGRP was significantly higher in the episodic migraine group than in the control group (50.61 ± 22.5 pg/mL versus 34.96 ± 17.03 pg/mL; p = 0.037). After treatment with neuromodulators no significant differences were found in the level of CGRP (46.11 ± 24.2 pg/mL basal versus 47.5 ± 24.88 pg/mL post-treatment). Neither were any differences found on analysing the topiramate and zonisamide groups individually.

CONCLUSIONS

The plasma level of CGRP is increased in episodic migraine, and its levels are not modified by treatment with low doses of topiramate or zonisamide.