Headache Disorders, Primary

• GSK Investigational Site — Chandler, Arizona, United States
• GSK Investigational Site — Irvine, California, United States
• GSK Investigational Site — Redondo Beach, California, United States
• GSK Investigational Site — San Francisco, California, United States

• GSK Investigational Site — Gilbert, Arizona, United States
• GSK Investigational Site — Litchfield Park, Arizona, United States
• GSK Investigational Site — Phoenix, Arizona, United States
• GSK Investigational Site — Phoenix, Arizona, United States

• Headache Research Unit. University Department of Neurology, Citadelle Hospital — Liège, Belgium
• Danish Headache Center & Department of Neurology, Glostrup Hospital, University of Copenhagen — Glostrup, Copenhagen, Denmark
• Servicio de Neurologia, Hospital Clinico Universitario — Valencia, Spain

• Arizona Neurological Institute — Scottsdale, Arizona, United States
• The Research Center of Southern California, LLC — Encinitas, California, United States
• USC Neurology — Los Angeles, California, United States
• UCSF Headache Center — San Francisco, California, United States

• Kocaeli University, Faculty of Medicine — Köseköy, Kocaeli, Turkey (Türkiye)

• GSK Investigational Site — Phoenix, Arizona, United States
• GSK Investigational Site — Phoenix, Arizona, United States
• GSK Investigational Site — Little Rock, Arkansas, United States
• GSK Investigational Site — Anaheim, California, United States

• Buckler Chiropractic — Phoenix, Arizona, United States
• Doctor's office — Scottsdale, Arizona, United States

Not specified

• Hôpital Notre-Dame — Montreal, Quebec, Canada

• Danish Headache Center Rigshospitalet - Glostrup — Glostrup Municipality, Denmark