How it is administered

Tioguanine is administered orally in the form of tablets. Each tablet typically contains 40 mg of tioguanine. The dosage and schedule depend on the specific blood cancer being treated and the patient's individual circumstances. The total daily dose may be given at one time.

How it works

Tioguanine is a type of chemotherapy medication known as a purine analogue. It works by interfering with the synthesis of nucleic acids (DNA and RNA) in cells. Specifically, tioguanine is incorporated into the DNA and RNA of rapidly dividing cells, such as cancer cells in the bone marrow. This incorporation disrupts the normal function and replication of these cells, leading to their death.

Tioguanine is converted in the body to active metabolites that inhibit several enzymes involved in the production of purine nucleotides, which are essential building blocks for DNA and RNA. By blocking these pathways, tioguanine prevents cancer cells from multiplying and spreading. Its effects are particularly strong in cells that are dividing quickly, which is why it is effective in treating certain types of leukemia.

Who Should take it

Tioguanine is indicated for the treatment of acute nonlymphocytic leukemias, including remission induction and consolidation phases. It is often used as part of a combination chemotherapy regimen, as this approach has been shown to result in more frequent and longer-lasting remissions compared to using tioguanine alone.

Tioguanine may also have some activity in the chronic phase of chronic myelogenous leukemia, but other medications are usually preferred for this condition. It is not effective in chronic lymphocytic leukemia, Hodgkin’s lymphoma, multiple myeloma, or solid tumors.

Who should not take it

Tioguanine should not be used in patients whose disease has previously shown resistance to this medication. There is usually complete cross-resistance between tioguanine and mercaptopurine, so if one is ineffective, the other is unlikely to work.

Patients with a known deficiency in the enzymes TPMT or NUDT15 may be at higher risk for severe side effects and may require significant dose reductions. Tioguanine should also be avoided in pregnant women due to its potential to cause harm to the fetus, and caution is advised in nursing mothers. It is not recommended for maintenance therapy or long-term continuous treatment because of the high risk of liver toxicity.

Commonly used with

Tioguanine is most often used in combination with other chemotherapy agents for the treatment of acute nonlymphocytic leukemias. Common partners include cytarabine, prednisone, cyclophosphamide, and vincristine. These combinations help increase the chances of remission and prolong the duration of response.

Commonly tested with

Tioguanine has been tested in clinical protocols alongside other chemotherapy drugs, particularly cytarabine, cyclophosphamide, prednisone, and vincristine, for the treatment of acute nonlymphocytic leukemias. It is also compared to or used with mercaptopurine in some studies, though cross-resistance is common.