Dr Armstrong received her bachelor's degree in pharmacy from Ferris State University and her Doctor of Pharmacy degree from Midwestern University. Dr Armstrong is a Board-Certified Pharmacotherapy Specialist (BCPS).

In her current position, Dr Armstrong serves as Vice President of Clinical Affairs with responsibility for the National Pharmacy & Therapeutics Committee process, Clinical Program Oversight process, and Pharmaceutical Pipeline Services at Caremark. Caremark is a prescription benefit management company (PBM). Dr Armstrong is also responsible for monitoring drug surveillance and communicating Pharmacy & Therapeutics Committee Formulary information to Caremark's internal and external customers.

Prior to joining Caremark, Inc, Dr Armstrong served as the Director of Drug Information Services at the University of Chicago Hospitals. She obtained 17 years of experience in a variety of clinical settings including critical care, hematology, oncology, infectious diseases, and clinical pharmacokinetics. Dr Armstrong played an active role in the education and training of medical, pharmacy, and nursing staff. She coordinated the Drug Information Center, the medical center's Adverse Drug Reaction Monitoring Program, and the continuing Education Program for pharmacists. She also maintained the hospital's strict formulary program and was the editor of the University of Chicago Hospitals' Formulary of Accepted Drugs and the drug information center's monthly newsletter Topics in Drug Therapy.

Dr Armstrong is an active member of the Academy of Managed Care Pharmacy (AMCP), the American Society of Health-Systems Pharmacists (ASHP), the American Pharmaceutical Association (APhA), the American College of Clinical Pharmacy (ACCP), and the Pharmacy & Therapeutics Society (P & T Society). Dr Armstrong wrote the chapter entitled "Drugs and Hormones Used in Endocrinology" in the 4th edition of the textbook Endocrinology. She is an Adjunct Clinical Instructor of Pharmacy Practice at Midwestern University. Dr Armstrong currently serves on the Drug Information Advisory Board for pharmacist.com and on the American Pharmaceutical Association Scientific Review Panel for Evaluations of Drug Interactions (EDI).