Thiopurine antimetabolite

Tioguanine (Specialist drug)

Tioguanine is an oral thiopurine antimetabolite used chiefly in the treatment of acute leukaemias. It is a specialist drug initiated under haematology supervision.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It is incorporated into nucleic acids as a fraudulent purine, disrupting DNA and RNA synthesis and producing cytotoxicity in dividing cells.

Prescribing in practice

It causes dose-related myelosuppression, so blood counts must be monitored regularly and the dose adjusted to avoid severe cytopenias.
Hepatotoxicity, including veno-occlusive disease and nodular regenerative hyperplasia, can occur, particularly with prolonged use, which limits its long-term role.
TPMT and NUDT15 status influences toxicity risk, and it is teratogenic, so effective contraception is advised.

Monitoring

Monitor full blood count frequently and liver function regularly, watching for signs of hepatic toxicity.

Counselling the patient

Attend for regular blood tests so your dose can be adjusted safely.
Report fever, sore throat, bruising, bleeding, yellowing of the skin or abdominal swelling promptly.
Use reliable contraception during treatment.

Evidence & guidelines

Use is guided by the manufacturer's SPC and specialist haematology protocols, with thiopurine metabolism testing recommended.

Reference: SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways