Inclusion criteria:
Men and women of 18 to 65 years
Diagnosis of chronic migraine (≥15 headache days a month for > 6 months)
Headaches must have at least two of the following characteristics: unilateral location, pulsating quality, moderate-severe pain intensity and/or aggravation by or causing avoidance of routine physical activity (e.g. Walking or climbing stairs), nausea and/or vomiting, photophobia and phonophobia
Informed and written consent
Exclusion criteria:
Previous treatment with botulinum toxin for chronic migraine
Previous treatment with botulinum toxin for cosmetic purposes with an interval of less than three months
Diagnosis of myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis or any other significant disease that might interfere with neuromuscular function
Subjects not willing to comply with the study visits
Subject is currently participating or has participated in the last 3 months in another clinical study in which the subject has, is, or will be exposed to an investigational or non-investigational drug or device
Confirmed allergy to botulinum toxin-A or any of the product components
Patients diagnosed with major depression
Patients diagnosed with any serious systemic diseases such as renal or hepatic failure, any other neurologic diseases like multiple sclerosis, epilepsy, and any other diseases that in the opinion of the investigator would put the patient at risk
Females of childbearing age with confirmed or suspected pregnancy, those planning on conceiving during the trial duration and women who are breastfeeding