thioguanine

Contraindicated in:

Hypersensitivity;
Tumors with demonstrated resistance to thioguanine or mercaptopurine (usually complete cross-resistance);
OB: Pregnancy;
Lactation: Lactation.

Use Cautiously in:

Infection;
↓bone marrow reserve;
Patients with homozygous TPMT enzyme deficiency or nucleotide diphosphatase (NUDT15) deficiency (substantial dose ↓ required to avoid hematologic adverse events);
Rep: Women of reproductive potential.

Adv. Reactions/Side Effects ⬆ ⬇

Derm: dermatitis, rash

EENT: loss of vibratory sense

GI: anorexia, diarrhea, hepatic veno-occlusive disease, hepatotoxicity, jaundice, nausea, stomatitis, vomiting

GU: gonadal suppression

Hemat: anemia, leukopenia, pancytopenia, thrombocytopenia

Metab: hyperuricemia

Neuro: unsteady gait

Interactions ⬆ ⬇

Drug-drug:

↑bone marrow depression with other antineoplastics or radiation therapy.
Sulfasalazine, olsalazine and mesalamine may ↑ levels and risk of toxicity.

Availability ⬆ ⬇

Route/Dosage ⬆ ⬇

PO (Adults and Children ): Induction: 2 mg/kg (75–100 mg/m²) once daily; after 4 wk, may ↑ to 3 mg/kg once daily. Maintenance: 2–3 mg/kg (100 mg/m²) once daily.

US Brand Names ⬆ ⬇

Action ⬆ ⬇

Incorporated into DNA and RNA, subsequently disrupting synthesis (cell-cycle S phase-specific).

Therapeutic effects:

Death of rapidly replicating cells, especially malignant ones.

Classifications ⬆ ⬇

Therapeutic Classification: antineoplastics

Pharmacologic Classification: antimetabolites

Pharmacokinetics ⬆ ⬇

Absorption: Variable and incomplete (average, 30%) following oral administration.

Distribution: Probably does not enter the CSF.

Metabolism/Excretion: Highly metabolized by the liver; undergoes methylation via thiopurine methyltransferase (TPMT).

Half-Life: 11 hr.

Canadian Brand Names ⬆ ⬇

Time/Action Profile ⬆ ⬇

(effect on blood counts)

ROUTE	ONSET	PEAK	DURATION
PO	7–10 days	14 days	21 days

Patient/Family Teaching ⬆ ⬇

Instruct patient to take thioguanine as directed, even if nausea and vomiting occur. If vomiting occurs shortly after dose is taken, consult health care professional.
Instruct patient to notify health care professional if ↓ urine output; swelling of lower extremities; yellowing of skin; nausea; vomiting; severe diarrhea; mouth sores; fever; chills; sore throat; signs of infection; bleeding gums; bruising; petechiae; or blood in urine, stool, or emesis occurs.
Caution patient to avoid crowds and persons with known infections. Instruct patient to use soft toothbrush and electric razor. Caution patient not to drink alcoholic beverages or take products containing aspirin or NSAIDs.
Instruct patient to inspect oral mucosa for redness and ulceration. If ulceration occurs, advise patient to use sponge brush and rinse mouth with water after eating and drinking. Topical agents may be used if pain interferes with eating. Stomatitis pain may require treatment with opioid analgesics.
Instruct patient not to receive any vaccinations without advice of health care professional.
Rep: May cause fetal harm. Advise female patients of reproductive potential to use effective contraception and to avoid breastfeeding during therapy. Advise patient to inform health care professional immediately if pregnancy is suspected. May cause gonadal suppression; however, patient should still use birth control. Instruct patient to discontinue thioguanine if intrahepatic cholestasis of pregnancy occurs.
Advise patient of need for medical follow-up and frequent lab tests.

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Indications ⬇

Contraind./Precautions ⬆ ⬇