硫鳥嘌呤
Thioguanine
2-Amino-6-mercaptopurine
別名: Tabloid · Lanvis · Tioguanina · NSC-752 · 6-thioguanine · 6-TG · 2-Amino-6-mercaptopurine · WR-1141
由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本
這是依體表面積（mg/m²）計算的劑量；給藥前須先將體重換算為體表面積。
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
各物種劑量
🌎 NA — North America🌍 EU — Europe
狗
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| 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 | 🌎 NA |
| Acute myelogenous leukemias (Protocol 1 & 2) | 50 mg/m2 PO q24-48h | PO | q24-48h | Ongoing | 🌎 NA |
- Acute lymphocytic and granulocytic leukemia: Consultation with a veterinary oncologist is strongly recommended.
- Acute myelogenous leukemias (Protocol 1 & 2): 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).
貓
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| 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 | 🌎 NA |
- Acute lymphocytic and granulocytic leukemia: Cats are particularly susceptible to hematologic effects.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。
概覽
硫鳥嘌呤 (Thioguanine, 6-TG) 是一種嘌呤抗代謝物抗腫瘤藥物，主要在獸醫學中用作犬貓急性淋巴性或粒細胞性白血病的輔助治療。
臨床要點：
- 它是一種細胞週期特異性藥物，主要作用於 S期（DNA合成期）。
- 雖然它與巰嘌呤 (mercaptopurine) 具有廣泛的交叉抗藥性，但其代謝途徑不同（不依賴黃嘌呤氧化酶進行降解），這使得其藥物交互作用與硫唑嘌呤或巰嘌呤有所不同。
- 其治療指數非常狹窄，需要嚴格監測血液學指標。
- 貓對其骨髓抑制作用特別敏感。
作用機轉
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.
安全性與警告
禁忌症
- Hypersensitivity to thioguanine
- Pregnancy (Category D - teratogenic and mutagenic)
不良反應
- Nausea
- Anorexia
- Vomiting
- Diarrhea
- Bone marrow suppression (leukopenia, thrombocytopenia, anemia)
- Hepatotoxicity
- Pancreatitis
- Gastrointestinal ulceration (including oral ulcers)
- Dermatologic reactions
注意事項
Strict Chemotherapy Safety Precautions Apply
- Hepatic/Renal Impairment: Use with extreme caution; dosage adjustments may be necessary.
- Pre-existing Conditions: Caution in patients with pre-existing bone marrow depression, active infections, or a history of urate urinary stones.
- Species Sensitivity: Cats are highly susceptible to hematologic toxicity.
- Reproduction: Potentially mutagenic and teratogenic. Do not use in pregnant animals. Nursing mothers should use milk replacer.
- Handling: Personnel and owners should follow safe handling protocols for cytotoxic drugs.
藥物交互作用
Increased risk of hepatotoxicity; use concurrently with caution.
Increased risk of severe infection due to additive immunosuppression.
Additive bone marrow depression; extreme caution required.
Increased risk of vaccine-induced infection or decreased vaccine efficacy; use with caution or avoid.
監測
- 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)
藥物動力學
吸收
Variable and incomplete; in humans, only about 30% of an oral dose is absorbed.
分佈
Distributes into the DNA and RNA of bone marrow (may require several doses). Does not readily enter the CNS. Crosses the placenta.
代謝
Rapidly metabolized primarily in the liver to a methylate derivative that is less active and less toxic than the parent compound.
排除
Metabolites are eliminated primarily in the urine.
過量
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).
可用產品
劑型
- Tablets
人用標示
- Thioguanine Tablets: 40 mg (Tabloid)
各地核准狀態
暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Store tablets in tight containers at room temperature.
飼主須知
這是一種用於治療某些類型白血病的強效化療藥物。由於藥效強烈，需要小心處理並密切監測。
- 安全處理： 給藥後請徹底洗手。請勿剝半或壓碎藥錠。孕婦、哺乳期婦女及免疫力低下者應避免接觸此藥物或寵物的排泄物。
- 廢棄物管理： 給藥後的幾天內，寵物的體液（尿液、糞便、嘔吐物）中可能含有微量藥物。清理排泄物時請戴上手套，清理後務必洗手。
- 注意事項： 如果您的寵物出現異常出血、瘀青、嚴重食慾不振、嘔吐、腹瀉、眼睛/牙齦發黃（黃疸）或感染跡象（如發燒或極度嗜睡），請立即聯繫您的獸醫師。
- 回診： 請務必按時進行所有預約的血液檢查。這些檢查對於確保藥物沒有損害寵物的骨髓或肝臟至關重要。
VetSheet 藥物參考供合格獸醫專業人員作臨床決策輔助之用，不能取代專業判斷或廠商最新仿單。