REVIEWMedications and Substances as a Cause of Headache: A Systematic Review of the LiteratureToth, CoryAuthor Information Department of Clinical Neurosciences, University of Calgary, Alberta, Canada Address correspondence and reprint requests to Dr. Cory Toth, Heritage Medical Research Building, Department of Clinical Neurosciences, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1; e-mail: email@example.com Clinical Neuropharmacology: May-June 2003 - Volume 26 - Issue 3 - p 122-136 Buy Abstract Medication- or substance-induced headache is probably an underrecognized entity with numerous etiologies, including prescribed medication, over-the-counter medication, illicit drugs, anesthetic agents, foods, food additives, beverages, vitamins, inhaled substances, and substances used in diagnostic procedures. The author performs a systemic review of the literature to provide an exhaustive description of the relationship between medications and substances and headaches of various types, along with pathophysiologic mechanisms whenever possible. Suggestions for improved identification of this phenomenon and its avoidance are provided. More scientific evaluation of substances and their possible association with headache is required with almost all substances indicated herein. © 2003 Lippincott Williams & Wilkins, Inc.