Website: PubMed


  • PhD in Pharmaceutical Sciences, University of Newcastle-upon-Tyne, England
  • BSc, Heriot-Watt University, Scotland
  • Postdoctoral Fellow, UW

Research Areas

  • Biochemistry of the human CYP2 and CYP4 families of P450s
  • Pharmacogenomics of cardiovascular drugs
  • P450-dependent bioactivation and associated adverse reactions

Taking Students: No


Dr. Rettie obtained a PhD in Pharmaceutical Sciences in 1983 from the University of Newcastle-upon-Tyne, England, before moving to Seattle to post-doc with Drs. Mont Juchau and Dr. Bill Trager at the UW in the areas of extra-hepatic drug metabolism and mechanisms of drug-drug interactions. He joined the faculty of the UW School of Pharmacy in 1987 and was Department Chair from 2000-2014.

Dr. Rettie’s research interests have focused mainly on the human P450 enzymes and attempts to understand mechanisms of catalysis, substrate specificity, pharmacogenetic variability and adverse drug reactions related to these monooxygenases. He has published over 190 peer-reviewed papers and held research grants from the National Institutes of Health (NIH) in these topic areas for the last 25 years.

Dr. Rettie has served on the editorial boards of Drug Metabolism and Disposition, Drug Metabolism Reviews, Journal of Pharmacology and Therapeutics, Current Drug Metabolism, Chemico-Biological Interactions and Chemical Research in Toxicology, as well as numerous NIH grant review panels. He has chaired the Scientific Affairs Committee of the International Society for Study of Xenobiotics (ISSX) and is Past Chair of the International Union of Basic and Applied Pharmacology’s Section of Drug Metabolism and Transport. In 2005, Dr. Rettie received the North American Scientific Achievement Award from ISSX for his work on elucidating metabolic and pharmacogenetic mechanisms of adverse reactions to the anticoagulant drug, warfarin, and in 2016 was appointed a Fellow of the Japanese Society for the Study of Xenobiotics.

Research Overview

Metabolism by the cytochrome P450s is the principal means whereby lipid-soluble drugs and compounds foreign to the body are converted to water-soluble derivatives that can be readily excreted. This is a beneficial effect of the enzyme system. However, it is well recognized that P450-mediated bioactivation of drugs and other xenobiotics is an important mechanism of chemical toxicity (Baillie and Rettie, 2011). Moreover, unexpected interruptions in P450 activity, due to genetic variation (Danese et al., 2012) or administration of agents that inhibit P450 activity (McDonald et al., 2015), can cause serious adverse drug reactions and contribute to disease states.

Much of the research in the Rettie laboratory focuses on the biochemistry and pharmacogenetics of the vitamin K cycle with an emphasis on how P450 enzymes interact with components of the cycle to maintain homeostasis. Human CYP2C9, for example, is the primary catalyst of (S)-warfarin metabolism (Daly et al., 2018). This vitamin K antagonist is an anticoagulant drug that is very difficult to dose correctly, and there are many drug-drug and drug-gene interactions associated with its use (Rettie and Tai, 2006).

An important goal for the laboratory is to define sources of inter-individual variability in warfarin dosing that can span a 100-fold range (Cooper et al., 2008). We have shown that common genetic polymorphisms in CYP2C9 decrease warfarin dose requirements by reducing the metabolic clearance of (S)-warfarin, while common polymorphisms in the warfarin target enzyme, VKORC1, affect warfarin dose by changing hepatic concentrations of this critical recycling enzyme (Rieder et al., 2005). We found that CYP4F2 and CYP4F11 are key vitamin K catabolizing enzymes (Edson et al., 2013) and common variation in CYP4F2 at least, affects warfarin dose, likely by modulating hepatic vitamin K concentrations (McDonald et al., 2009). We are currently examining the role of novel genetic variation in determining warfarin response in underserved populations (Henderson et al., 2019).

Other research in the laboratory is concerned with CYP4 enzymes that are potential drug targets because of their critical roles in health and disease (Edson et al., 2013; Johnson et al., 2015). Efforts are ongoing to synthesize chemical inhibitors of specific CYP4-family members to better dissect their physiological roles. CYP4B1 metabolizes a host of pro-toxins, including furans, aromatic amines, and certain fatty acids to reactive intermediates that can damage the cell. In this regard, CYP4B1 is a curious member of the CYP4 family because these enzymes typically have
a restricted substrate specificity that does not extend much beyond endogenous fatty acids. To evaluate the role of CYP4B1 in chemical toxicity, we have also developed a knockout mouse model (Parkinson et al, 2013). Most recently, we identified structural determinants of human CYP4B1 that confer high activity towards 4-ipomeanol (Wiek et al., 2015), and evaluated the substrate specificity of the ‘optimized’ human enzyme (Roellecke et al., 2017).

Our CYP4 research extends to the study of ‘orphan P450s’, like CYP4V2 and CYP4Z1, whose substrate specificity is unknown. We have reported on the fatty acid substrate specificity of CYP4V2 (Nakano et al., 2009) and the enzyme’s distribution in the eye (Nakano et al., 2012). Intriguingly, polymorphisms in CYP4V2 are found in patients suffering from the eye disease Bietti’s Crystalline Dystrophy (BCD). A knockout mouse model for CYP4V2 that recapitulates BCD has been developed in collaboration with the Kelly laboratory that should be of help in ‘deorphanizing’ the enzyme (Lockhart et al., 2014). Finally, the newest project in the Rettie lab concerns CYP4Z1, an unusual CYP that is localized to mammary tissue in humans and is up-regulated in breast cancer. We have expressed the enzyme in yeast and HepG2 cells and reported on the fatty acid metabolite profile of the enzyme (McDonald et al., 2017) and the development of novel, selective chemical inhibitors of CYP4Z1 (Kowalski et al., 2020).

In general, we use genetic re-engineering coupled with conventional protein biochemistry methods for the expression and isolation of CYP2 and CYP4 proteins and mutants of interest from heterologous hosts such as E.coli, insect cells and yeast (Mosher et al., 2008; Roberts et al., 2010). We also make extensive use of mass spectrometry for analyte quantification, including evaluation of structural changes in mutant proteins and lipidomic analysis to probe changes in endogenous metabolism due to CYP4V and CYP2C enzyme polymorphisms. Gene sequencing to discover novel polymorphisms in important pharmacogenes and disease-associated P450s is a continuing focus of the laboratory. Synthetic chemistry comes into play in the preparation of new substrates, inhibitors and metabolites for P450s of interest. Our long-term goals are to understand how structure and function are related for these important P450 enzyme families, and how their dysregulation affects drug response and disease.

Recent Publications

Translating kratom-drug interactions: from bedside to bench and back. Tanna RS, Cech NB, Oberlies NH, Rettie AE, Thummel KE, Paine MF. Drug Metab Dispos. 2023 Jun 7:DMD-MR-2022-001005. doi: 10.1124/dmd.122.001005. Online ahead of print.

Clinical Assessment of the Drug Interaction Potential of the Psychotropic Natural Product Kratom. Tanna RS, Nguyen JT, Hadi DL, Layton ME, White JR, Cech NB, Oberlies NH, Rettie AE, Thummel KE, Paine MF. Clin Pharmacol Ther. 2023 Jun;113(6):1315-1325. doi: 10.1002/cpt.2891. Epub 2023 Mar 28.

Spotlight on CYP4B1. Röder A, Hüsken S, Hutter MC, Rettie AE, Hanenberg H, Wiek C, Girhard M. Int J Mol Sci. 2023 Jan 20;24(3):2038. doi: 10.3390/ijms24032038.

A Physiological-Based Pharmacokinetic Model Embedded with a Target-Mediated Drug Disposition Mechanism Can Characterize Single-Dose Warfarin Pharmacokinetic Profiles in Subjects with Various CYP2C9 Genotypes under Different Cotreatments. Cheng S, Flora DR, Rettie AE, Brundage RC, Tracy TS. Drug Metab Dispos. 2023 Feb;51(2):257-267. doi: 10.1124/dmd.122.001048. Epub 2022 Nov 15.

Pharmacokinetic Modeling of Warfarin І – Model-based Analysis of Warfarin Enantiomers with a Target Mediated Drug Disposition Model Reveals CYP2C9 Genotype-dependent Drug-drug Interactions of S-Warfarin. Cheng S, Flora DR, Rettie AE, Brundage RC, Tracy TS. Drug Metab Dispos. 2022 Jul 7;50(9):1287-301. doi: 10.1124/dmd.122.000876. Online ahead of print.

Pharmacokinetic Modeling of Warfarin ІI – Model-based Analysis of Warfarin Metabolites following Warfarin Administered either Alone or Together with Fluconazole or Rifampin. Cheng S, Flora DR, Rettie AE, Brundage RC, Tracy TS. Drug Metab Dispos. 2022 Jul 7;50(9):1302-11. doi: 10.1124/dmd.122.000877. Online ahead of print.

Clinical Pharmacokinetic Assessment of Kratom (Mitragyna speciosa), a Botanical Product with Opioid-like Effects, in Healthy Adult Participants. Tanna RS, Nguyen JT, Hadi DL, Manwill PK, Flores-Bocanegra L, Layton ME, White JR, Cech NB, Oberlies NH, Rettie AE, Thummel KE, Paine MF. Pharmaceutics. 2022 Mar 11;14(3):620. doi: 10.3390/pharmaceutics14030620.

Adapting regulatory drug-drug interaction guidance to design clinical pharmacokinetic natural product-drug interaction studies: A NaPDI Center recommended approach. Cox EJ, Rettie AE, Unadkat JD, Thummel KE, McCune JS, Paine MF. Clin Transl Sci. 2022 Feb;15(2):322-329. doi: 10.1111/cts.13172. Epub 2021 Oct 26.

Massively parallel characterization of CYP2C9 variant enzyme activity and abundance. Amorosi CJ, Chiasson MA, McDonald MG, Wong LH, Sitko KA, Boyle G, Kowalski JP, Rettie AE, Fowler DM, Dunham MJ.

Pharmacokinetics, metabolism and off-target effects in the rat of 8-[(1H- benzotriazol-1-yl)amino]octanoic acid, a selective inhibitor of human cytochrome P450 4Z1: β-oxidation as a potential augmenting pathway for inhibition. Kowalski JP, Pelletier RD, McDonald MG, Kelly EJ, Rettie AE. Xenobiotica. 2021 Jun 11:1-15. doi: 10.1080/00498254.2021.1930281. Online ahead of print.

Modeling Pharmacokinetic Natural Product-Drug Interactions for Decision-Making: A NaPDI Center Recommended Approach. Cox EJ, Tian DD, Clarke JD, Rettie AE, Unadkat JD, Thummel KE, McCune JS, Paine MF. Pharmacol Rev. 2021 Apr;73(2):847-859. doi: 10.1124/pharmrev.120.000106.

In Vivo Functional Effects of CYP2C9 M1L, a Novel and Common Variant in the Yup’ik Alaska Native Population. Henderson LM, Hopkins SE, Boyer BB, Thornton TA, Rettie AE, Thummel KE. Drug Metab Dispos. 2021 May;49(5):345-352. doi: 10.1124/dmd.120.000301. Epub 2021 Feb 25.

Refined Prediction of Pharmacokinetic Kratom-Drug Interactions: Time-Dependent Inhibition Considerations. Tanna RS, Tian DD, Cech NB, Oberlies NH, Rettie AE, Thummel KE, Paine MF. J Pharmacol Exp Ther. 2021 Jan;376(1):64-73. doi: 10.1124/jpet.120.000270. Epub 2020 Oct 22.

Microphysiological system modeling of ochratoxin A-associated nephrotoxicity. Imaoka T, Yang J, Wang L, McDonald MG, Afsharinejad Z, Bammler TK, Van Ness K, Yeung CK, Rettie AE, Himmelfarb J, Kelly EJ. Toxicology. 2020 Nov;444:152582. doi: 10.1016/j.tox.2020.152582. Epub 2020 Sep 6.

Multiplexed measurement of variant abundance and activity reveals VKOR topology, active site and human variant impact. Chiasson MA, Rollins NJ, Stephany JJ, Sitko KA, Matreyek KA, Verby M, Sun S, Roth FP, DeSloover D, Marks DS, Rettie AE, Fowler DM. Elife. 2020 Sep 1;9:e58026. doi: 10.7554/eLife.58026.

Clinical Pharmacogenetics Implementation Consortium (CPIC) Guideline for CYP2C9 and HLA-B Genotypes and Phenytoin Dosing: 2020 Update. Karnes JH, Rettie AE, Somogyi AA, Huddart R, Fohner AE, Formea CM, Ta Michael Lee M, Llerena A, Whirl-Carrillo M, Klein TE, Phillips EJ, Mintzer S, Gaedigk A, Caudle KE, Callaghan JT. Clin Pharmacol Ther. 2021 Feb;109(2):302-309. doi: 10.1002/cpt.2008. Epub 2020 Sep 6.

Modulation of Major Human Liver Microsomal Cytochromes P450 by Component Alkaloids of Goldenseal: Time-Dependent Inhibition and Allosteric Effects. McDonald MG, Tian DD, Thummel KE, Paine MF, Rettie AE. Drug Metab Dispos. 2020 Oct;48(10):1018-1027. doi: 10.1124/dmd.120.091041. Epub 2020 Jun 26.

Heterologous Expression and Functional Characterization of Novel CYP2C9 Variants Identified in the Alaska Native People. McDonald MG, Henderson LM, Ray S, Yeung CK, Johnson AL, Kowalski JP, Hanenberg H, Wiek C, Thummel KE, Rettie AE. J Pharmacol Exp Ther. 2020 Aug;374(2):233-240. doi: 10.1124/jpet.120.265850. Epub 2020 May 18.

Design and Characterization of the First Selective and Potent Mechanism-Based Inhibitor of Cytochrome P450 4Z1. Kowalski JP, McDonald MG, Pelletier RD, Hanenberg H, Wiek C, Rettie AE. J Med Chem. 2020 May 14;63(9):4824-4836. doi: 10.1021/acs.jmedchem.0c00101. Epub 2020 Apr 30.

Associations of CYP2C9 and CYP2C19 Pharmacogenetic Variation with Phenytoin-Induced Cutaneous Adverse Drug Reactions. Fohner AE, Rettie AE, Thai KK, Ranatunga DK, Lawson BL, Liu VX, Schaefer CA. Clin Transl Sci. 2020 Sep;13(5):1004-1009. doi: 10.1111/cts.12787. Epub 2020 Apr 18.

A Novel LC-MS/MS Assay for Quantification of Des-carboxy Prothrombin and Characterization of Warfarin-Induced Changes. Basit A, Prasad B, Estergreen JK, Sabath DE, Alade N, Veenstra DL, Rettie AE, Thummel KE. Clin Transl Sci. 2020 Jul;13(4):718-726. doi: 10.1111/cts.12757. Epub 2020 Mar 9.

Novel insights into oxidation of fatty acids and fatty alcohols by cytochrome P450 monooxygenase CYP4B1. Thesseling FA, Hutter MC, Wiek C, Kowalski JP, Rettie AE, Girhard M. Arch Biochem Biophys. 2020 Jan 15;679:108216. doi: 10.1016/ Epub 2019 Dec 1.

Structure-Activity Relationships for CYP4B1 Bioactivation of 4-Ipomeanol Congeners: Direct Correlation between Cytotoxicity and Trapped Reactive Intermediates. Kowalski JP, McDonald MG, Whittington D, Guttman M, Scian M, Girhard M, Hanenberg H, Wiek C, Rettie AE. Chem Res Toxicol. 2019 Dec 16;32(12):2488-2498. doi: 10.1021/acs.chemrestox.9b00330. Epub 2019 Dec 4.

Interrogation of CYP2D6 Structural Variant Alleles Improves the Correlation Between CYP2D6 Genotype and CYP2D6-Mediated Metabolic Activity. Dalton R, Lee SB, Claw KG, Prasad B, Phillips BR, Shen DD, Wong LH, Fade M, McDonald MG, Dunham MJ, Fowler DM, Rettie AE, Schuetz E, Thornton TA, Nickerson DA, Gaedigk A, Thummel KE, Woodahl EL. Clin Transl Sci. 2020 Jan;13(1):147-156. doi: 10.1111/cts.12695. Epub 2019 Oct 25.

Assessing the clinical impact of CYP2C9 pharmacogenetic variation on phenytoin prescribing practice and patient response in an integrated health system. Fohner AE, Ranatunga DK, Thai KK, Lawson BL, Risch N, Oni-Orisan A, Jelalian AT, Rettie AE, Liu VX, Schaefer CA. Pharmacogenet Genomics. 2019 Oct;29(8):192-199. doi: 10.1097/FPC.0000000000000383.

Applying Multiplex Assays to Understand Variation in Pharmacogenes. Chiasson M, Dunham MJ, Rettie AE, Fowler DM. Clin Pharmacol Ther. 2019 Aug;106(2):290-294. doi: 10.1002/cpt.1468. Epub 2019 May 30.

A marijuana-drug interaction primer: Precipitants, pharmacology, and pharmacokinetics. Cox EJ, Maharao N, Patilea-Vrana G, Unadkat JD, Rettie AE, McCune JS, Paine MF. Pharmacol Ther. 2019 Sep;201:25-38. doi: 10.1016/j.pharmthera.2019.05.001. Epub 2019 May 7.

VKORC1 and Novel CYP2C9 Variation Predict Warfarin Response in Alaska Native and American Indian People. Henderson LM, Robinson RF, Ray L, Khan BA, Li T, Dillard DA, Schilling BD, Mosley M, Janssen PL, Fohner AE, Rettie AE, Thummel KE, Thornton TA, Veenstra DL. Clin Transl Sci. 2019 May;12(3):312-320. doi: 10.1111/cts.12611. Epub 2019 Mar 1.

A new LC-MS assay for the quantitative analysis of vitamin K metabolites in human urine. McDonald MG, Yeung CK, Teitelbaum AM, Johnson AL, Fujii S, Kagechika H, Rettie AE. J Lipid Res. 2019 Apr;60(4):892-899. doi: 10.1194/jlr.D087916. Epub 2019 Jan 22.

Influence of Stereochemistry on the Bioactivation and Glucuronidation of 4-Ipomeanol.Teitelbaum AM, McDonald MG, Kowalski JP, Parkinson OT, Scian M, Whittington D, Roellecke K, Hanenberg H, Wiek C, Rettie AE. J Pharmacol Exp Ther. 2019 Feb;368(2):308-316. doi: 10.1124/jpet.118.249771. Epub 2018 Nov 8.