# Thioguanine

Source: https://onco.cc/drugs/thioguanine/  
OnCo record `thioguanine` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Thioguanine (Tabloid) is an oral chemotherapy tablet used in some regimens to induce and consolidate remission in acute myeloid leukaemia; long-term use is avoided because it damages the liver.

## Summary

Thioguanine, a sibling of mercaptopurine from the Elion-Hitchings programme, was approved in 1966 for remission induction and consolidation of acute non-lymphocytic leukaemias. It appears in historical AML regimens such as DAT and TAD and in some childhood ALL protocols, but the label advises against maintenance or long-term use because of hepatic sinusoidal obstruction syndrome and nodular regenerative hyperplasia; the UK ALL97 trial confirmed excess liver toxicity when it replaced mercaptopurine in maintenance. Myelosuppression is dose-limiting, and TPMT-deficient patients need dose reduction.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-10
- Also known as: 6-TG; Tioguanine
- Tags: nci-list; generic
- Brand: Tabloid
- Modality: Thiopurine antimetabolite
- Mechanism: Guanine analogue converted to thioguanine nucleotides incorporated into DNA, causing strand breaks and cell death; inactivated by TPMT.
- Approvals: US 1966: Remission induction and consolidation of acute non-lymphocytic leukaemias

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Tioguanine
- US label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=thioguanine
- NCI drug page: https://www.cancer.gov/about-cancer/treatment/drugs/thioguanine

## Connected records

- drugs: [Mercaptopurine](https://onco.cc/drugs/mercaptopurine/)
- cancers: [Acute myeloid leukaemia](https://onco.cc/cancers/aml/), [High-risk acute lymphoblastic leukaemia in children (high-risk B-ALL and T-ALL)](https://onco.cc/cancers/all-paediatric-high-risk/), [Standard-risk B-cell acute lymphoblastic leukaemia in children](https://onco.cc/cancers/all-paediatric-standard-risk/)
- technologies: [Cytotoxic chemotherapy](https://onco.cc/technologies/cytotoxic-chemotherapy/), [TPMT and NUDT15 genotyping before thiopurines](https://onco.cc/technologies/tpmt-nudt15-genotyping/)
- trials: [AALL1231](https://onco.cc/trials/aall1231/), [AALL1331](https://onco.cc/trials/aall1331/), [Combination Chemotherapy in Treating Young Patients With Newly Diagnosed High-Risk B Acute Lymphoblastic Leukemia and Ph-Like TKI Sensitive Mutations](https://onco.cc/trials/nct02883049/), [Combination Chemotherapy, Biological Therapy, and Bone Marrow Transplantation in Treating Patients With Acute Myeloid Leukemia](https://onco.cc/trials/nct00002658/), [Inotuzumab Ozogamicin and Frontline Chemotherapy in Treating Young Adults With Newly Diagnosed B Acute Lymphoblastic Leukemia](https://onco.cc/trials/nct03150693/), [International Collaborative Treatment Protocol For Children And Adolescents With Acute Lymphoblastic Leukemia](https://onco.cc/trials/nct01117441/), [Response-Based Chemotherapy in Treating Newly Diagnosed Acute Myeloid Leukemia or Myelodysplastic Syndrome in Younger Patients With Down Syndrome](https://onco.cc/trials/nct02521493/)

---
JSON: https://onco.cc/api/v1/entities/thioguanine.json