環磷醯胺
Cyclophosphamide
N,N-bis(2-chloroethyl)-1,3,2-oxazaphosphinan-2-amine 2-oxide
別名: Cytoxan · Neosar · Procytox · Endoxana · CPM · CTX · B-518 · ciclofosfamida · cyclophosphamidum · cyclophosphanum · NSC-26271 · WR-138719 · Cytophosphane
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
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 |
|---|---|---|---|---|---|
| To inhibit local recurrence in dogs with incompletely resected soft tissue sarcomas | 10 mg/m2 PO once daily with piroxicam at 0.3 mg/kg PO once daily | PO | q24h | Continuous (metronomic) | 🌎 NA |
| Antineoplastic | 50 mg/m2 PO 4 days/week OR 250 mg/m2 PO once every 3 weeks OR 100-300 mg/m2 IV weekly | PO/IV | Varies | Protocol dependent | 🌎 NA |
| Immunosuppressant (IMHA/ITP) | 50 mg/m2 PO every 2nd day | PO | q48h | Adjust to manage side effects | 🌎 NA |
| Immunosuppressant (IMHA pulse therapy) | 50 mg/m2 PO daily for 4 days on, 3 days off | PO | Pulse | Ongoing | 🌎 NA |
| Polyarthritis | 1.5 mg/kg (>30 kg), 2 mg/kg (15-30 kg), 2.5 mg/kg (<15 kg) PO daily on 4 consecutive days each week | PO | 4 days/week | 2-4 months (max 4 months) | 🌎 NA |
| Glomerulonephritis | 2.2 mg/kg PO q24h for 4 days, discontinue for 3 days and then repeat | PO | Pulse | Ongoing | 🌎 NA |
| Lymphoma (COP low dose protocol - Induction) | 50 mg/m2 | PO | alternate days OR first 4 days of each week | First 2 months | 🌍 EU |
| Lymphoma (COP low dose protocol - Maintenance after 2 months) | 50 mg/m2 | PO | alternate days OR first 4 days of each second week | Months 2 to 6 | 🌍 EU |
| Lymphoma (COP low dose protocol - Maintenance after 6 months) | 50 mg/m2 | PO | q48h (one week in three) OR first 4 days of each third week | Months 6 to 12 | 🌍 EU |
- To inhibit local recurrence in dogs with incompletely resected soft tissue sarcomas: If unacceptable adverse effects develop, increase interval to every other day.
- Antineoplastic: Consult veterinary oncologist.
- Immunosuppressant (IMHA/ITP): Used with glucocorticoids.
- Immunosuppressant (IMHA pulse therapy): Alternatively 50 mg/m2 PO every other day.
- Polyarthritis: Given with prednisolone.
- Lymphoma (COP low dose protocol - Induction): Co-administer with 1 mg/kg furosemide q12h on treatment days to reduce cystitis risk.
- Lymphoma (COP low dose protocol - Maintenance after 2 months): Alternate-week therapy.
- Lymphoma (COP low dose protocol - Maintenance after 6 months): Stop and monitor for relapse after 12 months.
貓
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Immunosuppressant (ITP or IMHA) | 50 mg/m2 PO every 2nd day | PO | q48h | Ongoing | 🌎 NA |
| To slow progression of FIP | 2-4 mg/kg PO four times a week | PO | 4 times/week | Ongoing | 🌎 NA |
- Immunosuppressant (ITP or IMHA): Author prefers cyclosporine or chlorambucil in cats.
小型哺乳類
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Antineoplastic (lymphoma) in rabbits | 50 mg/m2 PO daily for 3 days each week OR 100-200 mg/m2 IV every 7 days | PO/IV | Varies | Protocol dependent | 🌎 NA |
- Antineoplastic (lymphoma) in rabbits: Consider fully implantable vascular access device for IV.
馬
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Neoplastic diseases | 200 mg/m2 (usually 1 gram per horse per dose) IV every 1-2 weeks | IV | q1-2 weeks | Protocol dependent | 🌎 NA |
- Neoplastic diseases: Consult veterinary oncologist.
羊
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Chemical shearing agent | Historical use | PO/IV | Single | Single | 🌎 NA |
- Chemical shearing agent: Historical use only.
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
環磷醯胺是一種強效的抗腫瘤和免疫抑制藥物，廣泛應用於犬貓的獸醫學中。
- 抗腫瘤用途：用於淋巴瘤、白血病、癌和肉瘤的聯合化療方案。低劑量節拍式（連續）療法也可用於預防肉瘤復發。
- 免疫抑制用途：用於嚴重的免疫介導疾病，如全身性紅斑狼瘡 (SLE)、免疫介導性血小板減少症 (ITP)、免疫介導性溶血性貧血 (IMHA) 和天皰瘡。
作用機轉
Cyclophosphamide is a prodrug that is metabolized in the liver by cytochrome P450 enzymes into active metabolites, primarily phosphoramide mustard and acrolein.
Phosphoramide mustard → acts as an alkylating agent → forms cross-links within and between DNA strands → interferes with DNA replication and RNA transcription → triggers apoptosis and cell death.
Acrolein is a toxic byproduct that concentrates in the urinary bladder and is responsible for sterile hemorrhagic cystitis. The drug also profoundly suppresses B-cell and T-cell function, leading to its immunosuppressive effects.
安全性與警告
禁忌症
- Prior anaphylactic reactions to the drug
- Severe pre-existing myelosuppression (leukopenia, thrombocytopenia)
- Active infections where immunosuppression may be dangerous
- No specific contraindications available in the monograph, but clinically contraindicated in patients with severe pre-existing myelosuppression or active haemorrhagic cystitis.
- Pre-existing severe myelosuppression
不良反應
- Myelosuppression (leukopenia, thrombocytopenia, anemia)
- Gastroenterocolitis (anorexia, nausea, vomiting, diarrhea)
- Sterile hemorrhagic cystitis (induced by acrolein metabolite)
- Alopecia (especially in continuously growing coats like Poodles and Old English Sheepdogs)
- Pulmonary infiltrates and fibrosis
- Hyponatremia
- Secondary leukemia
- Myelosuppression (nadir usually 5-14 days post-therapy)
- Sterile haemorrhagic cystitis (caused by acrolein metabolite)
- Bladder fibrosis
- Transitional cell carcinoma (secondary to chronic cystitis)
- Diarrhoea
- Hepatotoxicity
- Nephrotoxicity
- Reduction in hair growth rate / Alopecia
- Gastrointestinal toxicity
注意事項
WARNING: Cyclophosphamide is potentially teratogenic and embryotoxic. Safe use in pregnancy is not established.
- Hemorrhagic Cystitis: Up to 30% of dogs on long-term therapy may develop sterile hemorrhagic cystitis. Encourage frequent urination and water intake. Co-administration of furosemide may reduce risk.
- Myelosuppression: Monitor CBC closely. Delay doses if severe leukopenia or thrombocytopenia occurs.
- Handling: Cytotoxic precautions must be taken. Do not split or crush tablets. Avoid direct contact with urine or feces of treated animals.
藥物交互作用
May increase the myelosuppression caused by cyclophosphamide
Potentiation of cardiotoxicity may occur
May inhibit cyclophosphamide metabolism
May increase the rate of metabolism to active metabolites, increasing toxicity risk
May increase the myelosuppression caused by cyclophosphamide
Metabolism may be slowed, prolonging effects due to decreased pseudocholinesterases
Absorption of orally administered digoxin may be decreased (may occur several days after dosing)
Increase cyclophosphamide toxicity due to increased rate of conversion to metabolites
Reduce cyclophosphamide efficacy
Reduce cyclophosphamide efficacy
Insulin requirements are altered by concurrent cyclophosphamide
Inhibits hepatic cytochrome P450 enzyme pathway, potentially altering the metabolism and increasing toxicity of chemotherapeutics.
監測
- Efficacy (tumor response or remission of immune-mediated disease)
- Complete Blood Count (CBC) regularly for myelosuppression (nadir typically 7-14 days)
- Urinalysis regularly for signs of sterile hemorrhagic cystitis (hematuria)
- Uric acid levels (blood and urine)
- White Blood Cell (WBC) count (regular monitoring recommended due to myelosuppression)
- Urinalysis (monitor for haematuria indicating sterile haemorrhagic cystitis)
- Renal and hepatic function panels
- Free-catch urine by dipstick prior to and each week of treatment
- Haematology
- Biochemistry (prior to first treatment and minimum every 6 months)
藥物動力學
半衰期
吸收
Well absorbed after oral administration with peak levels occurring about 1 hour after dosing.
分佈
Distributed throughout the body, including CSF (subtherapeutic levels). Minimally protein bound. Distributes into milk and crosses the placenta.
代謝
Metabolized in the liver to several active and inactive metabolites (including phosphoramide mustard and acrolein).
排除
Majority of the drug is excreted as metabolites and unchanged drug in the urine.
過量
Limited information on acute overdoses. The lethal dose in dogs is reported as 40 mg/kg IV.
If an oral overdose occurs, perform gut emptying (emesis/lavage) if indicated and hospitalize the animal for aggressive supportive care, including IV fluids to flush the bladder and prevent hemorrhagic cystitis.
可用產品
劑型
- Oral tablets
- Powder for injection
- Compounded oral elixir/suspension
- Injectable: 100 mg, 200 mg, 500 mg, 1000 mg powder for reconstitution
- Oral: 50 mg tablets
人用標示
- Cyclophosphamide Tablets: 25 mg & 50 mg
- Cyclophosphamide Powder for Solution for Injection: 500 mg, 1 g and 2 g
- Endoxana 50 mg tablets
- Endoxana 100 mg, 200 mg, 500 mg, 1000 mg powder for reconstitution
各地核准狀態
Often requires compounding by specialized pharmacies (e.g., ChemoPet) for accurate veterinary dosing.
Often requires compounding by specialized pharmacies (e.g., ChemoPet) for accurate veterinary dosing.
暫無法規資料: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Store tablets and powder for injection at <25°C (brief excursions up to 30°C permitted). Store tablets in tight containers. Reconstituted injection is stable for 24 hours at room temperature or 6 days refrigerated. Compounded oral elixir is stable for 14 days refrigerated.
飼主須知
重要安全警告：這是一種強效化療藥物。請仔細遵循所有處理指示。
- 處理方式：請勿剝半或壓碎藥錠。處理後請徹底洗手。在寵物服藥期間，避免直接接觸其尿液、糞便或嘔吐物。
- 排尿：多帶您的狗散步以鼓勵排尿，尤其是在早晨。這有助於防止膀胱刺激。
- 何時聯繫獸醫：如果您發現寵物尿血、排尿困難、異常出血、瘀傷、嚴重嗜睡、嘔吐或腹瀉，請立即聯繫您的獸醫。
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