Calcitonin Gene-related Peptide Levels in Chronic Migraine

Twenty patients will be enrolled in a 2-site, 7-month, double-blind study conducted to evaluate a reduction in headache days and attacks and calcitonin gene-related peptide (CGRP) levels in saliva following treatment with OnabotulinumtoxinA versus saline. Eligible patients will be randomized and receive injections of OnabotulinumtoxinA or Saline at Visit 1. Following 3 months plus a 1 month wash out, patients will receive cross-over injections at Visit 5. Patients will return for monthly visits and exit the study at Visit 8. Patients will collect saliva at monthly intervals and document in a daily headache diary throughout the study .