Abstract
Thiopurine methyltransferase (TPMT) activity exhibits a monogenic codominant inheritance and catabolizes thiopurines. TPMT variant alleles are associated with low enzyme activity and pronounced pharmacologic effects of thiopurines. Loss-of-function alleles in the NUDT15 gene are common in Asians and Hispanics and reduce the degradation of active thiopurine nucleotide metabolites, also predisposing to myelosuppression. We provide recommendations for adjusting starting doses of azathioprine, mercaptopurine, and thioguanine based on TPMT and NUDT15 genotypes (updates on www.cpicpgx.org).
© 2018 The Authors Clinical Pharmacology & Therapeutics © 2018 American Society for Clinical Pharmacology and Therapeutics.
Publication types
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Practice Guideline
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Research Support, N.I.H., Extramural
MeSH terms
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Antimetabolites, Antineoplastic* / administration & dosage
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Antimetabolites, Antineoplastic* / pharmacokinetics
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Azathioprine* / administration & dosage
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Azathioprine* / pharmacokinetics
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Dose-Response Relationship, Drug
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Drug Dosage Calculations
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Humans
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Inactivation, Metabolic / genetics
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Mercaptopurine* / administration & dosage
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Mercaptopurine* / pharmacokinetics
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Methyltransferases / genetics*
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Pharmacogenetics
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Pharmacogenomic Testing
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Pyrophosphatases / genetics*
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Thioguanine* / administration & dosage
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Thioguanine* / pharmacokinetics
Substances
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Antimetabolites, Antineoplastic
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Mercaptopurine
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Methyltransferases
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TPMT protein, human
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NUDT15 protein, human
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Pyrophosphatases
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Thioguanine
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Azathioprine