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Pronunciation(thye oh GWAH neen)
U.S. Brand NamesTabloid®
Synonyms2-Amino-6-Mercaptopurine; NSC-752; TG; 6-TG; 6-Thioguanine; Tioguanine
Generic AvailableNo
Canadian Brand NamesLanvis®
UseTreatment of acute myelogenous (nonlymphocytic) leukemia; treatment of chronic myelogenous leukemia and granulocytic leukemia
Pregnancy Risk FactorD
LactationExcretion in breast milk unknown
ContraindicationsHypersensitivity to thioguanine or any component of the formulation; pregnancy
Warnings/PrecautionsThe U.S. Food and Drug Administration (FDA) currently recommends that procedures for proper handling and disposal of antineoplastic agents be considered. Use with caution and reduce dose of thioguanine in patients with renal or hepatic impairment. Not recommended for long-term continuous therapy due to potential for hepatotoxicity (hepatic veno-occlusive disease). Discontinue in patients with evidence of hepatotoxicity, including signs associated with portal hypertension. Thioguanine is potentially carcinogenic and teratogenic. Caution with history of previous therapy resistance with either thioguanine or mercaptopurine (there is usually complete cross resistance between these two). Patients with genetic deficiency of thiopurine methyltransferase (TPMT) or who are receiving drugs which inhibit this enzyme (mesalazine, olsalazine, sulfasalazine) may be highly sensitive to myelosuppressive effects.
Adverse Reactions>10%: Hematologic: Myelosuppressive: WBC: Moderate Platelets: Moderate Onset: 7-10 days Nadir: 14 days Recovery: 21 days 1% to 10%: Dermatologic: Skin rash Endocrine & metabolic: Hyperuricemia Gastrointestinal: Mild nausea or vomiting, anorexia, stomatitis, diarrhea Neuromuscular & skeletal: Unsteady gait <1%: Ascites, esophageal varices, hepatic necrosis, hepatitis, jaundice, LFTs increased, neurotoxicity, photosensitivity, portal hypertension, splenomegaly, thrombocytopenia, veno-occlusive hepatic disease
Overdosage/ToxicologySymptoms of overdose include bone marrow suppression, nausea, vomiting, malaise, hypertension, and sweating. Treatment is supportive. Dialysis is not useful.
Drug InteractionsAminosalicylates (olsalazine, mesalamine, sulfasalazine): May inhibit TPMT, increasing toxicity/myelosuppression of thioguanine. Use caution. Busulfan: Concurrent use may increase risk of hepatotoxicity and esophageal varices. Note: Allopurinol can be used in full doses with thioguanine unlike mercaptopurine.
Ethanol/Nutrition/Herb InteractionsFood: Enhanced absorption if administered between meals.
StabilityTablet: Store at room temperature. Injection (investigational in U.S.): Store intact vials under refrigeration (2°C to 8°C). Reconstitute injection with 5 mL SWFI, NS, or D5W to yield a 15 mg/mL solution. The reconstituted solution is stable for at least 24 hours under refrigeration. Further dilutions for infusion are stable for 24 hours at room temperature or under refrigeration.
CompatibilityCompatible: Stable in D5W, NS
Mechanism of ActionPurine analog that is incorporated into DNA and RNA resulting in the blockage of synthesis and metabolism of purine nucleotides
Pharmacodynamics/KineticsAbsorption: 30% (highly variable) Distribution: Crosses placenta Metabolism: Hepatic; rapidly and extensively via TPMT to 2-amino-6-methylthioguanine (active) and inactive compounds Half-life elimination: Terminal: 11 hours Time to peak, serum: Within 8 hours Excretion: Urine
DosageTotal daily dose can be given at one time; is sometimes ordered as 6-thioguanine, with 6 being part of the drug name and not a unit or strengthOral (refer to individual protocols): Infants and Children <3 years: Combination drug therapy for acute nonlymphocytic leukemia: 3.3 mg/kg/day in divided doses twice daily for 4 days Children and Adults: 2-3 mg/kg/day calculated to nearest 20 mg or 75-200 mg/m2/day in 1-2 divided doses for 5-7 days or until remission is attained Dosing comments in renal or hepatic impairment: Reduce dose
Monitoring ParametersCBC with differential and platelet count; liver function tests (weekly when beginning therapy then monthly, more frequently in patients with liver disease or concurrent hepatotoxic drugs); hemoglobin, hematocrit, serum uric acid; some laboratories offer testing for TPMT deficiencyHepatotoxicity may present with signs of portal hypertension (splenomegaly, esophageal varices, thrombocytopenia) or veno-occlusive disease (fluid retention, ascites, hepatomegaly with tenderness, or hyperbilirubinemia)
Patient EducationInform prescriber of all prescriptions, OTC medications, or herbal products you are taking, and any allergies you have. Do not take any new medication during therapy unless approved by prescriber. Take exactly as directed. Maintain adequate hydration (2-3 L/day of fluids) unless instructed to restrict fluid intake. May cause nausea and vomiting, diarrhea, or loss of appetite (small, frequent meals may help/request medication); weakness or lethargy (use caution when driving or engaging in tasks requiring alertness until response to drug is known); mouth sores (use good oral care); or headache (request medication). You will be susceptible to infection (avoid crowds and exposure to infection). Report signs or symptoms of infection (eg, fever, chills, sore throat, burning urination, fatigue); bleeding (eg, tarry stools, easy bruising); vision changes; unresolved mouth sores, nausea, or vomiting; CNS changes (hallucinations); or respiratory difficulty. Pregnancy/breast-feeding precautions: Do not get pregnant. Consult prescriber for appropriate contraceptive measures. The drug may cause permanent sterility and may cause birth defects. Consult prescriber if breast-feeding.
Dental Health: Effects on Dental TreatmentKey adverse event(s) related to dental treatment: Stomatitis.
Dental Health: Vasoconstrictor/Local Anesthetic PrecautionsNo information available to require special precautions
Mental Health: Effects on Mental StatusNone reported
Mental Health: Effects on Psychiatric TreatmentMyelosuppression is common; avoid clozapine and carbamazepine
Oncology: Emetic PotentialVery low (<10%)
Oncology: VesicantNo
Dosage FormsInjection, powder for reconstitution: 75 mg [investigational in U.S.] Tablet [scored]: 40 mg
Extemporaneously PreparedA 20 mg/mL oral suspension can be prepared by crushing fifteen 40 mg tablets in a mortar, and then adding 10 mL of methylcellulose 1% (in small amounts). Transfer to a graduate, then add a sufficient quantity of syrup to make 30 mL of suspension. Label "shake well." Room temperature stability is 60 days.Dressman JB and Poust RI, "Stability of Allopurinol and Five Antineoplastics in Suspension,"Am J Hosp Pharm, 1983, 40:616-8. Nahata MC, Morosco RS, and Hipple TF, 4th ed, Pediatric Drug Formulations, Cincinnati, OH: Harvey Whitney Books Co, 2000.
ReferencesBroxson EH, Dole M, Wong R, et al, "Portal Hypertension Develops in a Subset of Children With Standard Risk Acute Lymphoblastic Leukemia Treated With Oral 6-Thioguanine During Maintenance Therapy,"Pediatr Blood Cancer, 2004 [Epub October 24, 2004, prior to print]. Estlin EJ, "Continuing Therapy for Childhood Acute Lymphoblastic Leukaemia: Clinical and Cellular Pharmacology of Methotrexate, 6-Mercaptopurine and 6-Thioguanine,"Cancer Treat Rev, 2001, 27(6):351-63.
International Brand NamesLanvis® (AR, AU, BE, BG, BR, CA, CH, CL, CZ, FR, GB, HK, HR, IL, KW, NL, NZ, PL, RO, RU, SE, SG, SI, TH, TR, YU); Thioguanine-VHB® (IN); Thioguanine Wellcome® (IT); Thioguanin Glaxo Wellcome® (DE, IL); Thioguanin-GSK® (AT, DE); Tioguanina GSK® (ES)
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