Thioguanine

Indications

INDICATIONS AND USAGE a) Acute Nonlymphocytic Leukemias TABLOID brand Thioguanine is indicated for remission induction and remission consolidation treatment of acute nonlymphocytic leukemias. However, it is not recommended for use during maintenance therapy or similar long-term continuous treatments due to the high risk of liver toxicity (see WARNINGS and ADVERSE REACTIONS). The response to this agent depends upon the age of the patient (younger patients faring better than older) and whether thioguanine is used in previously treated or previously untreated patients. Reliance upon thioguanine alone is seldom justified for initial remission induction of acute nonlymphocytic leukemias because combination chemotherapy including thioguanine results in more frequent remission induction and longer duration of remission than thioguanine alone. b) Other Neoplasms TABLOID brand Thioguanine is not effective in chronic lymphocytic leukemia, Hodgkin’s lymphoma, multiple myeloma, or solid tumors.

Dosage and administration (summary)

DOSAGE AND ADMINISTRATION TABLOID brand Thioguanine is administered orally. The dosage which will be tolerated and effective varies according to the stage and type of neoplastic process being treated. Because the usual therapies for adult and pediatric acute nonlymphocytic leukemias involve the use of thioguanine with other agents in combination, physicians responsible for administering these therapies should be experienced in the use of cancer chemotherapy and in the chosen protocol. Patients with homozygous deficiency of either TPMT or NUDT15 enzyme typically require 10% or less of the standard thioguanine dosage.

Contraindications

CONTRAINDICATIONS Thioguanine should not be used in patients whose disease has demonstrated prior resistance to this drug. In animals and humans, there is usually complete cross-resistance between PURINETHOL (mercaptopurine) and TABLOID brand Thioguanine.

Warnings and precautions

WARNINGS SINCE DRUGS USED IN CANCER CHEMOTHERAPY ARE POTENTIALLY HAZARDOUS, IT IS RECOMMENDED THAT ONLY PHYSICIANS EXPERIENCED WITH THE RISKS OF THIOGUANINE AND KNOWLEDGEABLE IN THE NATURAL HISTORY OF ACUTE NONLYMPHOCYTIC LEUKEMIAS ADMINISTER THIS DRUG. THIOGUANINE IS NOT RECOMMENDED FOR MAINTENANCE THERAPY OR SIMILAR LONG-TERM CONTINUOUS TREATMENTS DUE TO THE HIGH RISK OF LIVER TOXICITY ASSOCIATED WITH VASCULAR ENDOTHELIAL DAMAGE (see DOSAGE AND ADMINISTRATION and ADVERSE REACTIONS).

Pregnancy

Pregnancy Drugs such as thioguanine are potential mutagens and teratogens. Thioguanine may cause fetal harm when administered to a pregnant woman. Thioguanine has been shown to be teratogenic in rats when given in doses 5 times the human dose.

Storage and supply

HOW SUPPLIED A biconvex, round white to off-white tablet, one side imprinted T40 and with a scorebar and the other side plain: in bottles of 25 tablets (NDC 80725-630-25). Store at 15° to 25°C (59° to 77°F) in a dry place.

Source: Thioguanine (Tabloid) — US FDA prescribing information, 2025-01-08, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.