Mitoxantrone

What is this medication for?

• Lymphoma (incl. rescue), transitional cell carcinoma, squamous cell carcinoma, mammary adenocarcinoma, renal adenocarcinoma, thyroid carcinoma, hemangiopericytoma
• Soft-tissue sarcomas; safer than doxorubicin in renal insufficiency (only ~10% renal clearance)

How is it given?

This medication is normally given by your veterinary team (in clinic or hospital).

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Dose-dependent stomach/intestinal distress (Common)

Worth a phone call to your veterinarian

• Bone marrow suppression (Dose-limiting)
• Cardiac toxicity (Far less than doxorubicin (class design point))

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Lethargy, seizures (Reported)

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Myelosuppression, concurrent infection, impaired cardiac function, prior cytotoxics/radiation
• has or has had: Hyperuricemia, hepatic impairment, hypersensitivity

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Other myelosuppressives
  • Hepatotoxic drugs

Storage and handling

Chemo gloves; into a vein infusion administration; protect from light per label.

Good to know

• The "doxorubicin for CKD cats" logic: minimal renal clearance (10%) removes the feline kidney damage constraint that complicates doxorubicin — with less cardiotoxicity as a bonus.
• Dose scale reminder: mitoxantrone ~6 mg/m² vs doxorubicin 30 mg/m² — a 5× mix-up is possible when switching protocols; read the drug name.
• Cat seizures during therapy = mitoxantrone signal (rare but documented).