John Horn

Research Professor Emeritus

Department of Pharmacy, Pharmacy Faculty

Fax: (206) 543-3835


Office Location: H375-V1 Box 357630 1959 NE Pacific St Seattle, WA 98195-7630

Website: PubMed

Research Interests

  • Drug interactions

Courses Taught

  • Pharmacy 561: Therapeutics II
  • Pharmacy 510: Clinical Applications of Drug Interactions


John Horn received his bachelor of pharmacy degree from Washington State University. He completed a clinical pharmacy residency at Deaconess Hospital in Spokane, Washington and obtained his Doctor of Pharmacy degree at the University of Cincinnati, Cincinnati, Ohio.

He has authored over 200 articles related to drug interactions. He is co-author of “The Top 100 Drug Interactions; A Guide to Patient Management,” a pocket-sized book of common drug interactions that is in its 13th edition. Dr. Horn has co-authored the reference text “Hansten and Horn’s Drug Interactions Analysis and Management” for over 20 years. “Drug Interactions Analysis and Management” is updated every three months and is recognized as the standard reference on drug interactions. These references have been translated into 5 languages and distributed to health care practitioners world-wide.

Dr. Horn is one of the founders of the Drug Interaction Foundation that has developed standardized methods of evaluating potential drug interactions and outcome-based criteria for rating the potential significance of drug interactions. He is a Fellow of the American College of Clinical Pharmacy and a member of the American Society of Health-Systems Pharmacists. He is currently chair of the Drug Interactions Specialty Panel for The Annals of Pharmacotherapy, a member of the editorial board of “Pharmacotherapy,” and serves as a reviewer for several medical and pharmaceutical journals.

Selected Publications

Horn JR, Gumpper KF, Hardy JC, McConnell PJ, Phansalkar S, Reilly C. Clinical decision support for drug-drug interactions: Improvement needed. Am J Health Syst Pharm. 2013 May 15;70(10):905-9.

Boyce RD, Horn JR, Hassanzadeh O, Waard Ad, Schneider J, Luciano JS, Rastegar-Mojarad M, Liakata M. Dynamic enhancement of drug product labels to support drug safety, efficacy, and effectiveness. J Biomed Semantics. 2013 Jan 26;4(1):5.

Boyce R, Collins C, Clayton M, Kloke J, Horn JR. Inhibitory Metabolic Drug Interactions with Newer Psychotropic Drugs: Inclusion in Package Inserts and Influences of Concurrence in Drug Interaction Screening Software.

Horn JR, Mantione MM, Johanson JF. OTC Polyethylene Glycol 3350 and the Pharmacist’s Role in Managing Constipation. J Am Pharm Assoc (2003). 2012 May-Jun;52(3):372-80.

Horn JR, Hansten PD, Osborn JD, Wareham P, Somani S. Customizing Clinical Decision Support to prevent excessive drug-drug interaction alerts. Am J Health Syst Pharm. 2011 Apr 15;68(8):662-4.

Wright AJ, Gomes T, Mamdani MM, Horn JR, Juurlink DN. The Risk of Hypotension Following Co-prescription of Macrolide Antibiotics and Calcium Channel Blockers. CMAJ. 2011 Feb 22;183(3):303-7.