Sean Hennessy, PharmD, PhD

faculty photo
Professor of Epidemiology in Biostatistics and Epidemiology
Department: Biostatistics and Epidemiology
Graduate Group Affiliations

Contact information
University of Pennsylvania
423 Guardian Drive
803 Blockley Hall
Philadelphia, PA 19104-6021
Office: 215-898-9112
Fax: 215-573-5315
BS (Pharmacy)
Philadelphia College of Pharmacy and Science, 1989.
PharmD (Clinical Pharmacy)
Philadelphia College of Pharmacy and Science, 1990.
MSCE (Clinical Epidemiology)
University of Pennsylvania School of Medicine, 1996.
PhD (Epidemiology with Biostatistics minor)
University of Pennsylvania, 2002.
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Description of Research Expertise

Sean Hennessy leads Penn's Center for Pharmacoepidemiology Research and Training (CPeRT), and conducts research in the field of pharmacoepidemiology, which is the study of the health effects of drugs and other medical products in populations. He and his colleagues identified a survival benefit of potassium supplementation in users of loop diuretics, and found that this survival benefit increases with hotter outdoor temperature. They also found that the survival benefits of statin drugs increases with hotter outdoor temperature. He and his colleagues study serious health consequences of drug-drug interactions involving high-risk drugs including anticoagulants, antidiabetes drugs, and antiplatelet agents. Their research has produced crucial knowledge about the cardiovascular safety of many widely-used drugs for mental health conditions in including ADHD, depression, and schizophrenia. They also evaluated an early approach to using health insurance data to improve prescribing, finding it ineffective despite its federal mandate. This contributed to the omission of a requirement for drug utilization review programs in Medicare Part D. He co-led a pair of studies that demonstrated the effectiveness and safety of the SA14-14-2 vaccine for Japanese encephalitis (JE), which subsequently led to the immunization of millions of children per year in populous countries including Cambodia, India, Malaysia, Nepal, Sri Lanka, and Thailand. Use of that vaccine has been credited with reducing the worldwide incidence of JE. He and his colleagues developed the trend-in-trend research design for studying the effects of rapidly increasing or declining exposures. He was the senior author of one of two citizen petitions to the US Food and Drug Administration that led to re-labeling of metformin, the best-proven therapy for type 2 diabetes, to permit its use in persons with mild to moderate renal insufficiency. He is chair of NIH's Health Services and Organizational Delivery study section, and an elected member of the US National Academy of Medicine.

Description of Other Expertise

Dr. Hennessy has served as scientific program chair and president of the International Society for Pharmacoepidemiology, regional editor for the Americas of the journal Pharmacoepidemiology and Drug Safety, as a member of FDA’s Drug Safety and Risk Management Advisory Committee, and on the board of directors of the American Society for Clinical Pharmacology and Therapeutics. He is a co-editor of the books Pharmacoepidemiology, 6th edition and Textbook of Pharmacoepidemiology, 2nd edition.

Additional Positions:
Director, Center for Pharmacoepidemiology Research & Training
Senior Scholar, Center for Clinical Epidemiology and Biostatistics
Senior Fellow, Leonard Davis Institute of Health Economics
Fellow, Institute on Aging
Member, Pharmacy and Therapeutics Committee, University of Pennsylvania Health System
Special Government Employee, US FDA
Chair, Health Services and Organizational Delivery Study Section, US NIH
Member, Council for International Organizations of Medical Sciences (CIOMS) Work Group XIII on Real-World Data & Evidence in Regulatory Decision Making

Courses Led:
EPI 666: Pharmacoepidemiology Research Methods

1998 Stanley A. Edlavitch Award for Best Abstract Submitted by a Student, International Society for Pharmacoepidemiology
2002 Saul Winegrad Award for Outstanding Dissertation in Epidemiology and Biostatistics, University of Pennsylvania
2005 Young Alumnus Award, University of the Sciences in Philadelphia
2008 Leon I Goldberg Young Investigator Award, American Society for Clinical Pharmacology & Therapeutics
2013 Samuel Martin Health Evaluation Sciences Research Award, University of Pennsylvania Perelman School of Medicine
2014 Julius W. Sturmer Memorial Lecture Award, Alpha Tau Chapter of the Rho Chi Society, Philadelphia College of Pharmacy, University of the Sciences
2015 Elected Member, National Academy of Medicine

Selected Publications

Pham Nguyen P, Chen Y, Thibault D, Leonard CE, Hennessy S, Willis A.: Does hospitalization for thromboembolism improve oral anticoagulant adherence in atrial fibrillation patients? Journal of the American Pharmacists Association 2020

Neuman MD, Hennessy S, Small DS, Newcomb C, Gaskins L, Brensinger CM, Wijeysundera DN, Bateman BT, Wunsch, H: Drug Enforcement Agency 2014 hydrocodone rescheduling rule and opioid dispensing after surgery. Anesthesiology 2020 DOI:10.1097/ALN.0000000000003188.

Nam YH, Han X, Brensinger CM, Bilker WB, Leonard CE, Hennessy S. : Sulfonylureas and metformin were not associated with an increased rate of serious bleeding in warfarin users: a self-controlled case series study. Clinical Pharmacology and Therapeutics 2020 (

Zhou M, Leonard CE, Brensinger CM, Bilker WB, Kimmel SE, Hecht TE, Hennessy S.: Pharmacoepidemiologic screening of potential oral anticoagulant drug interactions leading to thromboembolic events. Clinical Pharmacology and Therapeutics 2020 (

Nam YH, Brensinger CM, Bilker WB, Leonard CE, Hennessy S. : Non-confirmation of a signal of serious hypoglycemia with concomitant use of Alzheimer’s disease drugs with sulfonylureas. Epidemiology 2020 (forthcoming).

Miano TA, Shashaty MGS, Yang W, Brown JR, Zuppa A, Hennessy S: Effect of renin-angiotensin system inhibitors on the comparative nephrotoxicity of NSAIDs and opioids during hospitalization. Kidney360 2020 (doi:10.34067/KID.0001432020).

Nam YH, Brensinger C, Bilker WB, Leonard CE, Hennessy S: Investigation of concomitant use of Alzheimer’s disease drugs with sulfonylureas and serious hypoglycemia. Epidemiology 2020 (doi: 10.1097/EDE.0000000000001263).

George MD, Baker JF, Leonard CE, Mehta S, Miano TA, Hennessy S: Risk of Nonunion with Non-Selective NSAIDs, COX-2 inhibitors, and Opioids. Journal of Bone & Joint Surgery 2020 (DOI: 10.2106/jbjs.19.01415

Nam YH, Bilker WB, DeMayo FJ, Neuman MD, Hennessy S: Incidence rates of and risk factors for opioid overdose in new users of prescription opioids among US Medicaid enrollees: a cohort study. Pharmacoepidemiology and Drug Safety 2020 (DOI: 10.1002/pds.5067).

Abraham DS, Nguyen TPP, Hennessy S, Weintraub D, Gray SL, Xie D, Willis AW: Frequency of and risk factors for potentially inappropriate medication use in Parkinson’s disease. Age and Ageing 2020

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Last updated: 10/27/2020
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