氮芥 (Mechlorethamine)
**Mechlorethamine（氮芥）**是一種強效的細胞週期非特異性抗腫瘤藥物。在歷史上，它是第一個用於化學治療的氮芥類烷化劑。 在獸醫學中，它主要作為淋巴網狀內皮腫瘤的輔助治療，特別是作為復發性犬貓淋巴瘤的**MOPP救援方案**（Mechlorethamine, Oncovin [長春新鹼], Procarbazine, Prednisone）中的「M」。 > **臨床要點：** 氮芥是一種強烈的起泡劑（vesicant）。在靜脈注射時必須極度小心以避免藥物外滲，否則會導致嚴重的組織壞死和脫落。由於價格大幅上漲和供應問題，一些獸醫腫瘤學家在救援方案中會使用放線菌素D (dactinomycin) 或洛莫司汀 (CCNU) 來替代。 它也可以透過體腔內注射來治療惡性胸腔和腹腔積液，作為硬化劑促使漿膜表面沾黏。
作用機制: Mechlorethamine is a **bifunctional alkylating agent**. * **Mechanism:** It undergoes intramolecular cyclization to form a highly reactive aziridinium ion. This ion reacts with nucleophilic sites on DNA (primarily the N7 position of guanine). * **Pathway:** Alkylation → **Cross-linking of DNA strands** (interstrand and intrastrand) → Inhibition of DNA replication and RNA transcription → Cell death (apoptosis). * It is **cell cycle-phase nonspecific**, meaning it can kill cells in any phase of the cell cycle, though it is most toxic to rapidly dividing cells. * When given intracavitarily, it induces a strong inflammatory response on serous membranes, leading to sclerosis and obliteration of the cavity space.
各物種劑量
- Lymphoma rescue (MOPP protocol) · 3 mg/m2 IV · IV · given on days 0 and 7 (or days 0 and 14) of a 28 day protocol · 28 day cycles · Given as part of a protocol that includes vincristine (or vinblastine), procarbazine, and prednisone (or prednisolone).
- Lymphoma rescue (MOPP protocol) · 3 mg/m2 IV · IV · given on days 0 and 7 (or days 0 and 14) of a 28 day protocol · 28 day cycles · Given as part of a protocol that includes vincristine (or vinblastine), procarbazine, and prednisone (or prednisolone).
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Known infection
- Prior anaphylactic reaction to mechlorethamine
- Pregnancy (Category D teratogen)
- Anemia (relative)
- Bone marrow depression (relative)
- Tumor cell infiltration into bone marrow (relative)
- Patients who have received previous extensive chemotherapy or radiotherapy (relative)
不良反應
- Bone marrow depression (leukopenia, thrombocytopenia)
- Vomiting
- Nausea
- Ototoxicity (with high doses or regional perfusion)
- Alopecia
- Hyperuricemia
- Hepatotoxicity
- Peripheral neuropathy
- GI ulcers
- Severe tissue sloughing (if extravasated)
藥物相互作用
- Immunosuppressant drugs (e.g., azathioprine, cyclophosphamide, corticosteroids) · May increase the risk of severe infection.
- Myelosuppressive drugs (e.g., chloramphenicol, flucytosine, amphotericin B, colchicine) · Additive bone marrow depression; use with extreme caution.
- Live vaccines · Increased risk of vaccine-induced infection or decreased vaccine efficacy; use with caution or avoid.
監測
- CBC with platelets (at least every 1-2 weeks until stable; then every 3 months)
- Liver function tests (initially before starting treatment and then every 3-4 months)
- Injection site for any signs of extravasation (redness, swelling, pain)
過量
Because of the extreme toxic potential of this agent, overdoses must be strictly avoided. Dosages must be calculated carefully (usually based on Body Surface Area in m2). Overdose will likely result in profound, potentially fatal myelosuppression and severe gastrointestinal toxicity.
VetSheet 藥物參考供持牌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方最新藥品說明書。