Mechlorethamine
Also known as: Mustargen, Caryolysine, Onco-Cloramin
> **Important Safety Warning:** Mechlorethamine is a potent chemotherapy drug. Pregnant women, nursing mothers, and children should **not** handle this medication or clean up the pet's waste (urine, feces, vomit) for at least 48-72 hours after treatment. * **Monitor the Injection Site:** This drug can cause severe tissue damage if it leaks out of the vein. Check the IV site daily. If you notice any redness, swelling, pain, or licking at the site, contact your veterinarian immediately. * **Gastrointestinal Upset:** Nausea and vomiting are common. Your veterinarian may prescribe anti-nausea medications to help keep your pet comfortable. * **Infection Risk:** This drug lowers white blood cell counts, making your pet more susceptible to infections. Keep them away from sick animals and monitor for signs of illness, such as lethargy or fever. * **Nursing Pets:** If a nursing mother is receiving this drug, puppies or kittens must be switched to a milk replacer.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Lymphoma rescue (MOPP protocol)
- Lymphoma rescue (MOPP protocol)
How it is given
Possible side effects
- 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)
Cautions & contraindications
- 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)
- **Extravasation Risk:** Mechlorethamine is a potent vesicant. Extravasation will cause severe tissue necrosis and sloughing. Ensure a perfectly placed, clean IV catheter before administration. **Hazardous Drug:** This is a highly toxic antineoplastic agent. Strict hazardous drug handling protocols (gloves, gowns, biologic safety cabinet, closed-system transfer devices) must be utilized to protect veterinary personnel. **Teratogenicity:** It is a known teratogen and can suppress gonadal function. Pregnant women should absolutely avoid handling this drug or the patient's waste. **Hyperuricemia:** May raise serum uric acid levels; allopurinol may be required in susceptible patients.
Drug interactions
- 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.
Frequently asked questions
What is Mechlorethamine used for in pets?
> **Important Safety Warning:** Mechlorethamine is a potent chemotherapy drug. Pregnant women, nursing mothers, and children should **not** handle this medication or clean up the pet's waste (urine, feces, vomit) for at least 48-72 hours after treatment. * **Monitor the Injection Site:** This drug can cause severe tissue damage if it leaks out of the vein. Check the IV site daily. If you notice any redness, swelling, pain, or licking at the site, contact your veterinarian immediately. * **Gastrointestinal Upset:** Nausea and vomiting are common. Your veterinarian may prescribe anti-nausea medications to help keep your pet comfortable. * **Infection Risk:** This drug lowers white blood cell counts, making your pet more susceptible to infections. Keep them away from sick animals and monitor for signs of illness, such as lethargy or fever. * **Nursing Pets:** If a nursing mother is receiving this drug, puppies or kittens must be switched to a milk replacer.
Is Mechlorethamine safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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