Tioguanine

Tioguanine

Clinical data
Trade names	Lanvis, Tabloid, others
AHFS/Drugs.com	International Drug Names
MedlinePlus	a682099
Routes of administration	by mouth
ATC code	L01BB03 (WHO)
Pharmacokinetic data
Bioavailability	30% (range 14% to 46%)
Metabolism	Intracellular
Biological half-life	80 minutes (range 25-240 minutes)
Identifiers
IUPAC name 2-amino-1H-purine-6(7H)-thione
CAS Number	154-42-7 Y
PubChem (CID)	2723601
IUPHAR/BPS	6845
DrugBank	DB00352 Y
ChemSpider	2005804 Y
UNII	WIX31ZPX66 Y
KEGG	D08603 Y
ChEBI	CHEBI:9555 N
ChEMBL	CHEMBL727 Y
ECHA InfoCard	100.005.299
Chemical and physical data
Formula	C5H5N5S
Molar mass	167.193 g/mol
3D model (Jmol)	Interactive image
SMILES S=C2/N=C(\Nc1ncnc12)N
InChI InChI=1S/C5H5N5S/c6-5-9-3-2(4(11)10-5)7-1-8-3/h1H,(H4,6,7,8,9,10,11) Y Key:WYWHKKSPHMUBEB-UHFFFAOYSA-N Y
NY (what is this?)

Tioguanine, also known as thioguanine or 6-thioguanine (6-TG) is a medication used to treat acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), and chronic myeloid leukemia (CML). Long term use is not recommended. It is given by mouth.

Common side effects include bone marrow suppression, liver problems and inflammation of the mouth. It is recommended that liver enzymes be checked weekly when on the medication. People with a genetic deficiency in thiopurine S-methyltransferase are at higher risk of side effects. Avoiding pregnancy when on the medication is recommended for both males and females. Tioguanine is in the antimetabolite family of medications. It is a purine analogue of guanine and works by disrupting DNA and RNA.

Tioguanine was between 1949 and 1951. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale price in the developing world is about 7.07 USD per 40 mg pill as of 2014. In the United Kingdom this amount costs the NHS about 4.14 pounds.

The major concern that has inhibited the use of thioguanine has been veno-occlusive disease (VOD) and its histological precursor nodular regenerative hyperplasia (NRH). The incidence of NRH with thioguanine was reported as between 33-76%. The risk of ensuing VOD is serious and frequently irreversible so this side effect has been a major concern. However, recent evidence using an animal model for thioguanine-induced NRH/VOD has shown that, contrary to previous assumptions, NRH/VOD is dose dependent and the mechanism for this has been demonstrated. This has been confirmed in human trials, where thioguanine has proven to be safe but efficacious for coeliac disease when used at doses below those commonly prescribed. This has led to a revival of interest in thioguanine because of its higher efficacy and faster action compared to other thiopurines and immunosuppressants such as mycophenylate.