Annotation of DPWG Guideline for thioguanine and TPMT
Summary
Select an alternative drug or reduce the initial dose of thioguanine for patients that are TPMT poor metabolizers and reduce initial dose for patients that are TPMT intermediate metabolizers.
Specify a genotype or phenotype for specific annotations
Alleles not present in the above pull-down menus have no recommendation.
Annotation
Read more about how PharmGKB curates DPWG guidelines using extra information provided by DPWG to enable the interactive genotype tool above.
August 2019 Update
The Royal Dutch Pharmacists Association - Pharmacogenetics Working Group has evaluated therapeutic dose recommendations for thioguanine based on TPMT genotype. They recommend reducing the initial dose for patients that are intermediate metabolizers and selecting an alternative drug or reducing the initial dose for patients that are poor metabolizers. They updated the wording for the intermediate metabolizer recommendation, reflected in the table below.
Wording in table taken from the Dutch guidelines August 2019 update.
Read for more information about this recommendation, Read about gene information from DPWG
Preemptive genotyping
Excerpts from the DPWG risk analysis document for thioguanine and TPMT:
The Dutch Pharmacogenetics Working Group considers genotyping before starting thioguanine to be essential for drug safety. Genotyping must be performed before drug therapy has been initiated to guide drug and dose selection.
Read more about how DPWG assigns their recommendations for preemptive genotyping.
November 2018 Update
The Royal Dutch Pharmacists Association - Pharmacogenetics Working Group has evaluated therapeutic dose recommendations for thioguanine based on TPMT genotype. They recommend reducing the initial dose for patients that are intermediate metabolizers and selecting an alternative drug or reducing the initial dose for patients that are poor metabolizers.
Wording in table taken from the Dutch guidelines November 2018 update.
2011 Guideline
The Royal Dutch Pharmacists Association - Pharmacogenetics Working Group has evaluated therapeutic dose recommendations for thioguanine based on TPMT genotype [Article:21412232]. They recommend selecting an alternative drug for patients carrying inactive alleles.