티오구아닌
티오구아닌(6-TG)은 주로 개와 고양이의 급성 림프구성 또는 과립구성 백혈병의 보조 치료제로 사용되는 **퓨린 대사 길항제** 항종양제입니다. **임상 요점:** * 이 약물은 **세포주기 특이적** 약물로, 주로 **S기**(DNA 합성기)에 작용합니다. * 머캅토푸린과 광범위한 교차 내성을 공유하지만, 대사 경로가 다릅니다(분해에 크산틴 산화효소를 필요로 하지 않으므로 아자티오프린이나 머캅토푸린과 상호작용 프로필이 다름). * 치료 지수가 매우 좁아 혈액학적 수치에 대한 엄격한 모니터링이 필요합니다. * 고양이는 특히 골수 억제 효과에 민감합니다.
작용 기전: Thioguanine acts as a false purine base. * **Intracellular Activation:** It is converted by the enzyme **hypoxanthine-guanine phosphoribosyltransferase (HGPRT)** → **thioguanine monophosphate (TGMP)**. * **DNA/RNA Incorporation:** TGMP is further phosphorylated into di- and tri-nucleotides, which are then incorporated into **DNA and RNA**. * **Cytotoxicity:** The insertion of these fraudulent nucleotides disrupts normal nucleic acid synthesis and function, leading to DNA strand breaks and **apoptosis**. * It also causes feedback inhibition of *de novo* purine synthesis, further starving the cancer cells of essential nucleotides.
동물 종별 용량
- Acute lymphocytic and granulocytic leukemia · 25 mg/m2 PO once daily (q24 hours) for 1-5 days, then every 30 days thereafter as necessary · PO · q24h initially, then q30d · 1-5 days initially, then ongoing · Cats are particularly susceptible to hematologic effects.
- Acute lymphocytic and granulocytic leukemia · 40 mg/m2 PO once daily (q24 hours) for 4-5 days, then every 3rd day thereafter · PO · q24h initially, then q72h · 4-5 days initially, then ongoing · Consultation with a veterinary oncologist is strongly recommended.
- Acute myelogenous leukemias (Protocol 1 & 2) · 50 mg/m2 PO q24-48h · PO · q24-48h · Ongoing · Used as part of a protocol with Cytarabine (100 mg/m2 SC daily for 2-6 days) +/- Doxorubicin (10 mg/m2 IV once a week).
용량은 면허 수의 전문가를 위한 임상 참고 자료입니다. 항상 최신 라벨과 개별 환자에 대해 확인하십시오.
투여 경로
금기
- Hypersensitivity to thioguanine
- Pregnancy (Category D - teratogenic and mutagenic)
이상반응
- Nausea
- Anorexia
- Vomiting
- Diarrhea
- Bone marrow suppression (leukopenia, thrombocytopenia, anemia)
- Hepatotoxicity
- Pancreatitis
- Gastrointestinal ulceration (including oral ulcers)
- Dermatologic reactions
약물 상호작용
- Hepatotoxic drugs (e.g., halothane, ketoconazole, valproic acid, phenobarbital, primidone) · Increased risk of hepatotoxicity; use concurrently with caution.
- Immunosuppressive drugs (e.g., azathioprine, cyclophosphamide, corticosteroids) · Increased risk of severe infection due to additive immunosuppression.
- Myelosuppressive drugs (e.g., chloramphenicol, flucytosine, amphotericin B, colchicine) · Additive bone marrow depression; extreme caution required.
- Live vaccines · Increased risk of vaccine-induced infection or decreased vaccine efficacy; use with caution or avoid.
모니터링
- Hemograms (including platelets) initially every 1-2 weeks, then every 1-2 months on maintenance. (Dose reduction of 25% recommended if WBC drops to 5,000-7,000 cells/mm3; discontinue if < 5,000 cells/mm3 until resolved)
- Liver function tests
- Serum amylase (if pancreatitis is suspected)
- Clinical efficacy (remission status)
과용량
Toxicity from overdosage can manifest as **acute** (severe gastrointestinal effects like nausea, vomiting, diarrhea) or **delayed** (profound bone marrow depression, hepatotoxicity, severe gastroenteritis). **Treatment:** * If ingestion was recent, use standard protocols to empty the GI tract (emesis/gastric lavage followed by activated charcoal), keeping in mind the risks of handling cytotoxic emesis. * Provide aggressive supportive care (IV fluids, broad-spectrum antibiotics if neutropenic, blood products if severely anemic or thrombocytopenic).
VetSheet 약물 레퍼런스는 면허 수의 전문가를 위한 임상 의사결정 보조 도구이며, 전문적 판단이나 제조사의 최신 라벨을 대신하지 않습니다.