Program leadership
Kristen M. Bamberg, PharmD, MS, BCPS, BCCCP
PGY1 Pharmacy Residency Program Director
Lead Critical Care Pharmacist
Kristen M. Bamberg, PharmD, MS, BCPS, BCCP, earned her doctor of pharmacy degree in 2002 from Midwestern University’s College of Pharmacy in Glendale, AZ, and has been practicing at Flagstaff Medical Center (FMC) since 2004. Serving as the Lead Critical Care Pharmacist since 2008, Bamberg manages pharmaceutical care as well as nursing and provider education across three critical care units: Medical-Surgical, Cardiovascular and Trauma, and the 40-bed Progressive Care Unit at FMC’s Level I Trauma Center. Her role, which extends beyond direct patient care, includes evidence-based protocols, total parenteral nutrition management, pharmacokinetic consultations and anticoagulation management.
Bamberg has earned multiple honors, including the 2024 American Association of Colleges of Pharmacy Preceptor of the Year Award and the Northern Arizona Healthcare Dean Taylor Health Care Award. She holds dual board certifications in critical care pharmacy and pharmacotherapy, and serves as Chair and Vice Chair of the Board of Pharmacy Specialties’ Critical Care Pharmacy Council, and holds additional leadership positions with the American College of Clinical Pharmacy and Society of Critical Care Medicine. Her dedication to advancing patient care, clinical pharmacy and education is reflected in her many career achievements.
A true adventurer at heart, Bamberg is inspired by the outdoors. She enjoys camping with her husband and two dogs, taking scenic road trips in her Shelby GT Mustang and unwinding with a knitting project. She believes family, friends and relaxation are the key to a balanced life.
Scott Waldrop, PharmD
Northern Arizona Healthcare (NAH) System Director of Pharmacy
Arizona native Scott Waldrop, PharmD, earned a doctorate of pharmacy and completed a PGY1 at the University of Arizona. He began his career at Yavapai Regional Medical Center in Prescott Valley as a clinical coordinator. He went on to serve as director of pharmacy at various Phoenix hospital systems, including John C. Lincoln and Banner Health. He joined Flagstaff Medical Center in 2018 as the NAH system director of pharmacy.
Pharmacists
Jaci Constable, PharmD, BCPS
NAH System Pharmacy Clinical Manager
Jaci Constable, PharmD, BCPS,earned her doctor of pharmacy degree in 2012 from the University of Missouri in Kansas City. After working at a large medical center in Springfield, Constable moved to Arizona in 2017, joining Flagstaff Medical Center as a Clinical Staff Pharmacist, where she later became Lead Pharmacist in Pediatrics and Internal Medicine. In 2025, she was promoted to System Clinical Manager.
Constable is a curious traveler, lifelong reader and dedicated dog mom. She finds inspiration in exploring new places, reading books and the quiet intelligence of ravens. She values connection, curiosity and the stories that shape our world.
Tereza Foscolos, PharmD, BCPS
Clinical Staff Pharmacist
Tereza Foscolos, PharmD, BCPS, earned her doctor of pharmacy degree in 2019 from the University of Connecticut. After graduating, Foscolos joined Flagstaff Medical Center as a Clinical Staff Pharmacist. Her expertise includes process improvement and policy implementation. She has been involved in Blood Refusal Trauma Modifications, multiple therapeutic interchanges and formulary expansions.
Outside of work, Foscolos enjoys horseback riding, embracing the freedom of the open trail and exploring the beautiful scenery around Flagstaff.
Drew Gifford, PharmD, BCOP
Lead Oncology Pharmacist
Drew Gifford, PharmD, BCOP, earned his doctor of pharmacy degree in 2012 from Midwestern University’s College of Pharmacy in Glendale, AZ. Gifford’s career began in outpatient pharmacy settings, in a leadership role serving oncology patients. In 2019, he joined Northern Arizona Healthcare to start the Outpatient Oncology Infusion Center and, that same year, became a board-certified Oncology Pharmacist (BCOP).
Gifford is passionate about advancing patient care through precision medicine and genetic testing. He expertly optimizes chemotherapy regimens and compassionately supports patients through their treatment journeys, all while ensuring the best possible outcomes through personalized, evidence-based care.
Beyond the pharmacy, Gifford enjoys whipping up creative confections in his kitchen, strategizing over a good board game and staying active through various sports. Whether refining treatment plans or perfecting a new recipe, he brings the same enthusiasm and attention to detail to everything he does.
Blake Lewis, PharmD, BCPS
Clinical Staff Pharmacist
After spending several years doing research in a behavioral pharmacology lab, Blake Lewis, PharmD, BCPS,earned his doctor of pharmacy degree in 2018 from the University of Montana in Missoula. In 2019, Lewis completed his post-graduate year (PGY)1 Residency at East Jefferson General Hospital in Metairie, LA, and moved to Arizona to join Flagstaff Medical Center as a Clinical Staff Pharmacist. From day one, he has been an incredible asset to the team, expertly caring for patients across pediatrics, critical care and oncology.
In his free time, Lewis enjoys relaxing with his family and playing the guitar.
Megan Marsh, PharmD
PGY1 Pharmacy Residency Coordinator
Clinical Staff Pharmacist
Megan Marsh, PharmD, earned her doctor of pharmacy degree in 2015 from Purdue University in West Lafayette, IN, and completed her post-graduate year (PGY)1 Pharmacy Residency at Northwestern University in Evanston, IL. She also completed a PGY2 Ambulatory Care Pharmacy Residency and a PGY2 Cardiology Pharmacy Residency. Marsh joined Flagstaff Medical Center in 2025 after gaining significant acute care experience at Vail Health Hospital in Vail, CO, and Brigham and Women’s Hospital in Boston. She has quickly become an invaluable member of the clinical pharmacy team.
Whether she’s training for endurance events or exploring new trails with her three dogs, Marsh is an avid runner who thrives on movement. She loves to travel and experience different cultures, visiting six of the seven continents, with Africa next on her list. When she’s not pursuing professional goals, she’s hiking, gardening or going for a walk. She values balance, adventure and making the most of every opportunity, whether it’s across the globe or right in her own backyard.
Nicholas Massie, PharmD, BCCCP, BCEMP
Lead Emergency Department Pharmacist
Nicholas Massie, PharmD, BCCCP, BCEMP,earned his doctor of pharmacy degree in 2012 from Auburn University in AL. Massie then completed a post-graduate year (PGY)1 General Practice Residency and a PGY2 Critical Care Residency at Huntsville Hospital, a Level I Trauma and Major Cardiac Center, in AL.
Massie serves as the Lead Emergency Medicine Clinical Pharmacist and PGY1 Residency Preceptor at Flagstaff Medical Center. His professional interests include emergency medicine, acute trauma, critical care, infectious diseases and the emerging applications of artificial intelligence in health care. As a preceptor, he is passionate about fostering clinical excellence, critical thinking and adaptability in high-acuity environments.
Originally from Birmingham, Massie is a proud fan of the University of Alabama. Outside of work, he enjoys international travel, physical fitness, handloading ammunition and shooting sports, ham radio, and reading non-fiction, fiction, and philosophy.
Linda McCusker, BSPharm, MBA, BCPS
Clinical Staff Pharmacist
Linda McCusker, BSPharm, MBA, BCPS, earned her pharmacy degree in 1992 from West Virginia University in Morgantown. She also earned a master’s degree in business administration in 2001 from the University of Pittsburgh.
As an Intensive Care Unit-trained pharmacist at Flagstaff Medical Center, Linda has been a key contributor to the inpatient pharmacy since joining in 2002. She specializes in critical care and trauma and has a special interest in anticoagulation management, antibiotic stewardship and working across teams to provide interdisciplinary care for patients. Linda volunteers on multiple quality improvement and clinical advancement projects, creating positive change for future pharmacists.
Outside of work, Linda enjoys renovating her historic 1912 home, hiking with her dogs and traveling to Europe to explore wine regions. Having earned a Wine & Spirit Education Trust (WSET) Level 3 Award in Wines, she dreams of one day owning a wine bar. Linda stays active through swimming, backpacking, and spin classes, all while balancing life with her blended family.
Amy Sannes, PharmD
Clinical Staff Pharmacist
Amy Sannes, PharmD, earned her doctor of pharmacy degree in 2011 from the University of North Carolina at Chapel Hill. Sannes began her professional career serving adult patients in a hospital pharmacy setting before completing her post-graduate year (PGY)1 Pharmacy Residency at Intermountain Medical Center in Murray, UT, in 2013. She then cared for pediatric patients at Intermountain Health Primary Children’s Hospital in Salt Lake City before joining Flagstaff Medical Center in 2022, where she cares for patients of all ages.
Outside of work, Sannes enjoys hiking and backpacking through northern Arizona and southern Utah. She also trains her Danish-Swedish Farmdog, Skizzle, for agility, obedience and scent sports.
Stephen Shaw, PharmD
Clinical Staff Pharmacist
Stephen Shaw, PharmD, earned his doctor of pharmacy degree in 2016 from the University of Colorado in Denver. Shaw then completed a post-graduate year (PGY)1 Residency at the U.S. Department of Veterans Affairs in Denver before joining Flagstaff Medical Center’s Intensive Care Unit and Emergency Department clinical pharmacy teams.
Outside of work, Shaw enjoys hiking northern Arizona’s scenic trails, reading novels and short stories, and brewing craft beer. He shares life’s adventures with his wife, young son, and their dog and cat.
Beth Stalker, PharmD
Pharmacy Operations Manager
Beth Stalker, PharmD, earned her doctor of pharmacy degree in 2021 from the University of Arizona in Tucson. Stalker has worked in pharmacy settings for over 20 years and has held various leadership roles focusing on quality improvement and regulatory compliance. Passionate about mentoring the next generation of pharmacists, she is deeply committed to fostering professional growth through hands-on learning and real-world application.
Stalker values lifelong learning and balance. Outside of work, she enjoys reading, hiking, practicing yoga and spending time with her dogs.
Brittney Witmer, PharmD, BCIDP
NAH System Lead Antimicrobial Stewardship Pharmacist
Brittney Witmer, PharmD, BCIDP, earned her doctor of pharmacy degree in 2015 from the University of Arizona in Tucson before completing a post-graduate year (PGY)1 Residency at the U.S. Department of Veterans Affairs in Denver. Witmer joined Flagstaff Medical Center in 2016 as a Clinical Staff Pharmacist and transitioned into the Lead Antimicrobial Stewardship role in 2023. Her expertise in antimicrobial stewardship is a significant contribution to the field, supporting safe and effective treatments.
Outside of work, Witmer enjoys hiking, baking, traveling and exploring new cuisines. She thrives on discovery and creativity and has a deep love for learning, often indulging in infectious disease podcasts that fuel her intellectual curiosity. Above all, she cherishes quality time with her family, especially her son and husband. Her family shares their home with a rescue cat and dog who add a special warmth and love to their life.