Mitoxantrone
Also known as: Novantrone
> **Important Chemotherapy Safety** > Your pet is receiving a potent chemotherapy drug. The drug and its breakdown products can be found in your pet's urine for up to 6 days and in their feces for up to 7 days after treatment. * **Waste Management:** Wear disposable gloves when cleaning up urine, feces, or vomit. Double-bag the waste before placing it in the regular trash. Wash your hands thoroughly afterward. * **Color Changes:** You may notice your pet's urine turning a **blue-green color**, or a slight bluish tint to the whites of their eyes (sclera). **Do not panic**—this is a normal, harmless effect of the drug's dark blue dye. * **Side Effects to Watch For:** Monitor your pet closely for loss of appetite, vomiting, diarrhea, or extreme lethargy. Because this drug lowers white blood cell counts, your pet is at a higher risk for infection. * **When to Call the Vet:** Contact your veterinarian immediately if your pet develops a fever, severe vomiting/diarrhea, or if a cat experiences any seizure activity.
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
- Soft-tissue sarcomas
- Effective dose (general)
- Single rescue agent for lymphoma
- Transitional cell carcinoma
- Lymphoma, squamous cell carcinoma, transitional cell carcinoma, mammary gland tumors, etc.
- Single rescue agent for lymphoma
- Rescue agent for canine lymphoma
- Transitional cell carcinoma after laser ablation of the primary tumor
How it is given
Possible side effects
- Dose-dependent GI distress (vomiting, anorexia, diarrhea)
- Bone marrow depression (neutropenia, sepsis; nadir typically around day 10)
- Non-regenerative anemia
- Lethargy
- Seizures (specifically noted in cats)
- Blue-green discoloration of urine and sclera (benign)
- Tissue necrosis or phlebitis (if extravasated, though less severe than doxorubicin)
- Rarely: conjunctivitis, jaundice, renal failure, allergic reactions, thrombocytopenia
- Gastrointestinal signs (vomiting, anorexia, diarrhoea)
- Bone marrow depression (WBC nadir generally at 10 days)
- Seizure activity (reported in cats)
- Blue discoloration of urine and sclera (very rare)
Cautions & contraindications
- Severe pre-existing myelosuppression
- Concurrent active infection
- Significantly impaired cardiac function
- Patients with prior extensive cytotoxic drug or radiation exposure (relative)
- Pregnancy (FDA Category D) and nursing mothers
- Pre-existing myelosuppression
- Concurrent infection
- Hepatic disease
- Impaired cardiac function
- **Handling Precautions:** Mitoxantrone is a cytotoxic agent. Strict adherence to safe handling, administration, and disposal protocols for chemotherapeutic agents is mandatory to protect veterinary personnel. **Extravasation Risk:** While generally considered an irritant rather than a severe vesicant like doxorubicin, extravasation can still cause tissue necrosis. Ensure a perfectly placed, clean IV catheter before administration. **Organ Function:** Use with caution in patients with impaired hepatic function or hyperuricemia/hyperuricuria.
Drug interactions
- Doxorubicin, Daunorubicin, or Radiation Therapy: Cardiotoxicity risks may be enhanced in patients that have previously received these therapies to the mediastinum.
- Immunosuppressant Drugs (e.g., azathioprine, cyclophosphamide, corticosteroids): Concurrent use may significantly 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; should be used with extreme caution or avoided during therapy.
- Myelosuppressive agents: Increased risk of severe bone marrow depression
- Immunosuppressive agents: Increased risk of severe immunosuppression and infection
- Heparin: Chemically incompatible
Frequently asked questions
What is Mitoxantrone used for in pets?
> **Important Chemotherapy Safety** > Your pet is receiving a potent chemotherapy drug. The drug and its breakdown products can be found in your pet's urine for up to 6 days and in their feces for up to 7 days after treatment. * **Waste Management:** Wear disposable gloves when cleaning up urine, feces, or vomit. Double-bag the waste before placing it in the regular trash. Wash your hands thoroughly afterward. * **Color Changes:** You may notice your pet's urine turning a **blue-green color**, or a slight bluish tint to the whites of their eyes (sclera). **Do not panic**—this is a normal, harmless effect of the drug's dark blue dye. * **Side Effects to Watch For:** Monitor your pet closely for loss of appetite, vomiting, diarrhea, or extreme lethargy. Because this drug lowers white blood cell counts, your pet is at a higher risk for infection. * **When to Call the Vet:** Contact your veterinarian immediately if your pet develops a fever, severe vomiting/diarrhea, or if a cat experiences any seizure activity.
Is Mitoxantrone 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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