thioguanine (Rx)

Brand and Other Names:6TG, 6Thioguanine, more...Tabloid
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 40mg

Acute Nonlymphocytic Leukemia

2 mg/kg/day PO  

Cautiously increase to 3 mg/kg/day if no response after 4 weeks

May be used in multi-drug therapy, including prednisone, cytarabine, cyclophosphamide, vincristine

Monitor: CBC, LFTs

Take on empty stomach to reduce risk of nausea and vomiting

Dosage Forms & Strengths

tablet

  • 40mg

Acute Nonlymphocytic Leukemia

2 mg/kg/day PO  

Cautiously increase to 3 mg/kg/day if no response after 4 weeks

May be used in multi-drug therapy, including prednisone, cytarabine, cyclophosphamide, vincristine

Monitor: CBC, LFTs

Take on empty stomach to reduce risk of nausea and vomiting

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Interactions

Interaction Checker

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      Serious - Use Alternative

        Significant - Monitor Closely

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            Contraindicated (0)

              Serious - Use Alternative (8)

              • adenovirus types 4 and 7 live, oral

                thioguanine decreases effects of adenovirus types 4 and 7 live, oral by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressives may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection). Live-attenuated vaccines should be avoided for at least 3mo after cessation of immunosuppressive therapy.

              • deferiprone

                deferiprone, thioguanine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid use of deferiprone with other drugs known to be associated with neutropenia or agranulocytosis; if an alternative is not possible, monitor absolute neutrophil count more frequently.

              • influenza virus vaccine quadrivalent, adjuvanted

                thioguanine decreases effects of influenza virus vaccine quadrivalent, adjuvanted by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive drugs may reduce the immune response to influenza vaccine.

              • influenza virus vaccine trivalent, adjuvanted

                thioguanine decreases effects of influenza virus vaccine trivalent, adjuvanted by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Immunosuppressive drugs may reduce the immune response to influenza vaccine.

              • palifermin

                palifermin increases toxicity of thioguanine by Other (see comment). Avoid or Use Alternate Drug. Comment: Palifermin should not be administered within 24 hrbefore, during infusion of, or within 24 hr after administration of antineoplastic agents. Coadministration of palifermin within 24 hr of chemotherapy resulted in increased severity and duration of oral mucositis.

              • pexidartinib

                thioguanine and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

              • pretomanid

                thioguanine, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.

              • tofacitinib

                thioguanine, tofacitinib. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.

              Monitor Closely (18)

              • acalabrutinib

                acalabrutinib, thioguanine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

              • allopurinol

                allopurinol, thioguanine. unknown mechanism. Use Caution/Monitor. Potential for increased myelosuppression.

              • belatacept

                belatacept and thioguanine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

              • busulfan

                thioguanine, busulfan. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Avoid concomitant administration of thioguanine with busulfan because of potential for hepatotoxicity. .

              • cholera vaccine

                thioguanine decreases effects of cholera vaccine by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Immunosuppressive therapies, including irradiation, antimetabolites, alkylating agents, cytotoxic drugs and corticosteroids (used in greater than physiologic doses), may reduce the immune response to cholera vaccine.

              • dengue vaccine

                thioguanine decreases effects of dengue vaccine by immunosuppressive effects; risk of infection. Use Caution/Monitor. Immunosuppressive therapies (eg, irradiation, antimetabolites, alkylating agents, cytotoxic drugs, corticosteroids [greater than physiologic doses]) may reduce immune response to dengue vaccine.

              • fingolimod

                thioguanine increases effects of fingolimod by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Concomitant therapy is expected to increase the risk of immunosuppression. Use caution when switching patients from long-acting therapies with immune effects. .

              • hydroxyurea

                thioguanine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • influenza A (H5N1) vaccine

                thioguanine decreases effects of influenza A (H5N1) vaccine by Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce immune response to H5N1 vaccine.

              • influenza virus vaccine (H5N1), adjuvanted

                thioguanine decreases effects of influenza virus vaccine (H5N1), adjuvanted by Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Immunosuppressive therapies may reduce immune response to H5N1 vaccine.

              • mechlorethamine

                mechlorethamine, thioguanine. pharmacodynamic synergism. Use Caution/Monitor. Coadministration with mechlorethamine may increase the risk of immunosuppression and myelosuppression.

              • meningococcal group B vaccine

                thioguanine decreases effects of meningococcal group B vaccine by pharmacodynamic antagonism. Use Caution/Monitor. Individuals with altered immunocompetence may have reduced immune responses to the vaccine.

              • ofatumumab SC

                ofatumumab SC, thioguanine. Either increases effects of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Consider the risk of additive immune system effects when coadministering immunosuppressive therapies with coadministration. When switching from therapies with immune effects, take into account the duration and mechanism of action of these therapies when initiating ofatumumab SC.

              • olaparib

                thioguanine and olaparib both increase pharmacodynamic synergism. Use Caution/Monitor. Coadministration with other other myelosuppressive anticancer agents, including DNA damaging agents, may potentiate and prolongate the myelosuppressive toxicity.

              • siponimod

                siponimod and thioguanine both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution if coadministered because of additive immunosuppressive effects during such therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs to avoid unintended additive immunosuppressive effects.

              • sipuleucel-T

                thioguanine decreases effects of sipuleucel-T by pharmacodynamic antagonism. Modify Therapy/Monitor Closely.

              • trastuzumab

                trastuzumab, thioguanine. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .

              • trastuzumab deruxtecan

                trastuzumab deruxtecan, thioguanine. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .

              Minor (4)

              • maitake

                maitake increases effects of thioguanine by pharmacodynamic synergism. Minor/Significance Unknown. Maitake mushroom has anti-tumor effects (animal/in vitro research).

              • taurine

                thioguanine decreases levels of taurine by unspecified interaction mechanism. Minor/Significance Unknown.

              • vitamin A

                vitamin A, thioguanine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Antioxidants such as vitamin A enhance the efficacy, and reduce toxicity, of antineoplastic drugs.

              • vitamin E

                vitamin E, thioguanine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Antioxidants such as vitamin E enhance the efficacy, and reduce toxicity, of antineoplastic drugs.

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              Adverse Effects

              Frequency Not Defined

              Anorexia

              Stomatitis

              Vomiting

              Nausea

              Myelosuppression

              Hyperuricemia

              Nephrotoxicity

              Hepatotoxicity

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              Warnings

              Contraindications

              Hypersensitivity; prior resistance to 6-thioguanine or mercaptopurine

              Cautions

              Therapy should be administered only by physicians experienced with the risks of therapy and with knowledge on the natural history of acute nonlymphocytic leukemias

              Long-term continuous therapy associated with high risk for hepatotoxicity, portal hypertension, or sinusoidal obstruction syndrome; monitor liver function closely and discontinue therapy if patient experiences symptoms of hepatotoxicity, including hyperbilirubinemia, hepatomegaly, portal hypertension such as thrombocytopenia out of proportion with neutropenia and splenomegaly; elevations of liver enzymes have also been reported in association with liver toxicity but do not always occur

              The most consistent, dose-related toxicity is bone marrow suppression, which may be manifested by anemia, leukopenia, thrombocytopenia, or any combination of these; any one of these findings may also reflect progression of underlying disease; since thioguanine may have a delayed effect, it is important to withdraw medication temporarily at first sign of an abnormally large fall in any of formed elements of blood

              Evaluate patients with repeated severe myelosuppression for thiopurine S-methyltransferase (TPMT) or nucleotide diphosphatase (NUDT15) deficiency; TPMT genotyping or phenotyping (red blood cell TPMT activity) and NUDT15 genotyping can identify patients who have reduced activity of these enzymes; patients with homozygous TPMT or NUDT15 deficiency require substantial dosage reductions; bone marrow suppression could be exacerbated by co-administration with drugs that inhibit TPMT, such as olsalazine, mesalazine, or sulphasalazine

              Obtain evaluation of the hemoglobin concentration or hematocrit, total white blood cell count and differential count, and quantitative platelet count frequently while on thioguanine therapy; in cases where cause of fluctuations in formed elements in peripheral blood is obscure, bone marrow examination may be useful for evaluation of marrow status; the decision to increase, decrease, continue, or discontinue a given dosage of thioguanine must be based not only on the absolute hematologic values, but also upon rapidity with which changes are occurring; in many instances, particularly during induction phase of acute leukemia, complete blood counts will need to be done more frequently in order to evaluate effect of therapy; dosage of thioguanine may need to be reduced when combined wi

              Myelosuppression is often unavoidable during induction phase of adult acute nonlymphocytic leukemias if remission induction is to be successful; whether or not this demands modification or cessation of dosage depends both upon response of underlying disease and a careful consideration of supportive facilities (granulocyte and platelet transfusions) which may be available; life-threatening infections and bleeding have been observed as consequences of thioguanine-induced granulocytopenia and thrombocytopenia

              Therapy is potentially carcinogenic

              Institute adequate hydration and administer allopurinol prophylactically to minimize risk of hyperuricemia, which commonly occurs with treatment

              Monitor for infections (leukopenia)

              Monitor for bleeding (thrombocytopenia)

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              Pregnancy & Lactation

              Pregnancy Category: D

              Lactation: not known if excreted in breast milk, do not nurse

              Pregnancy Categories

              A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

              B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

              C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

              D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

              X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

              NA: Information not available.

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              Pharmacology

              Mechanism of Action

              Purine analog that is incorporated into DNA and RNA and inhibits purine ribonucleotide synthesis

              Pharmacokinetics

              Half-Life: 15 min (initial phase); 5-9 hr (terminal phase)

              Absorption: 30%

              Time to peak: 8hr (serum)

              Metabolism: Liver

              Metabolites: 2-amino-6-methylthiopurine, inorganic sulfate, thiouric acid

              Excretion: Urine

              Dialyzable: No

              Pharmacogenomics

              Converted via thiopurine S-methyltransferase (TPMT) to 2-amino-6-methylthioguanine (MTG, active metabolite) and inactive metabolites

              Complete TPMT deficiency is rare in the general population (0.3%); increased myelosuppression when used with TPMT deficiency

              Alleles associated with decreased TPMT enzymatic activity are TPMT*2, TPMT*3A, and TPMT*3C

              Companies providing genetic testing

              • The following companies currently offer testing for TPMT variants
              • Prometheus Labs (http://www.prometheuslabs.com/)
              • Arup Laboratories (http://www.aruplab.com/)
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              Images

              BRAND FORM. UNIT PRICE PILL IMAGE
              Tabloid oral
              -
              40 mg tablet

              Copyright © 2010 First DataBank, Inc.

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              Patient Handout

              Patient Education
              thioguanine oral

              THIOGUANINE - ORAL

              (THYE-oh-GWA-neen)

              COMMON BRAND NAME(S): Tabloid

              USES: Thioguanine is used to treat a certain type of cancer (acute myeloid leukemia-AML). It is a chemotherapy drug that works by slowing or stopping the growth of cancer cells.

              HOW TO USE: Take this medication by mouth with or without food as directed by your doctor, usually once daily. Drink plenty of fluids while taking this medication unless otherwise directed by your doctor. Doing so may help decrease the risk of certain side effects (kidney problems).The dosage is based on your medical condition, weight, and response to treatment. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day.Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.

              SIDE EFFECTS: Nausea, vomiting, loss of appetite, and mouth sores may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.Tell your doctor right away if you have any serious side effects, including: joint pain/swelling, black stools, vomit that looks like coffee grounds, symptoms of liver disease (such as nausea/vomiting that doesn't stop, stomach/abdominal pain, yellowing eyes/skin, dark urine).This medication may decrease bone marrow function, an effect that may lead to a low number of blood cells such as red cells, white cells, and platelets. This effect can cause anemia, decrease your body's ability to fight an infection, or cause easy bruising/bleeding. Tell your doctor right away if you develop any of the following symptoms: unusual tiredness, pale skin, signs of infection (such as sore throat that doesn't go away, fever, chills), easy bruising/bleeding.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

              PRECAUTIONS: Before taking thioguanine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, certain enzyme disorders (TPMT or NUDT15 deficiency).Thioguanine can make you more likely to get infections or may worsen any current infections. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using thioguanine. Thioguanine may harm an unborn baby. Ask about reliable forms of birth control while using this medication. If you become pregnant, talk to your doctor right away about the risks and benefits of this medication.It is unknown if this drug passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

              DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

              OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

              NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, liver/kidney function) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

              MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

              STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

              MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).

              Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

              IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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              Formulary

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              Tier Description
              1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
              2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
              3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
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              NC NOT COVERED – Drugs that are not covered by the plan.
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