Cytarabine (Ara-C)

What is this medication for?

• Lymphoreticular neoplasms, myeloproliferative disease (leukemias), CNS lymphoma

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

• Infusion strategy changes the organ reach: bolus = plasma only; CRI over 2–3 days = meaningful CSF levels — that's why CNS-lymphoma protocols specify the drip.

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

• Conjunctivitis (human high-dose) (Class effect — consider lubricant drops)

Worth a phone call to your veterinarian

• Myelosuppression (low white blood cell counts prominent) (Primary toxicity)
• stomach/intestinal toxicity (Possible)

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

• Trouble breathing, collapse, seizures, severe vomiting or diarrhea, facial swelling, or pale gums

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

• has or has had: Hypersensitivity; marrow suppression (relative)
• has or has had: Monitoring essential; infection risk during nadir

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

Storage and handling

Chemo handling; reconstituted solutions stable ~24 h at room temperature (refrigeration extends per label); preservative-free vials.

Good to know

• Infusion strategy changes the organ reach: bolus = plasma only; CRI over 2–3 days = meaningful CSF levels — that's why CNS-lymphoma protocols specify the drip.
• The COP protocol's quiet third member (with cyclophosphamide + prednisolone) — 100 mg/m² divided under the skin is the classic affordable feline lymphoma backbone.
• S-phase specificity → effective only against cells in DNA synthesis during exposure; hence divided dosing/infusion schedules rather than single pushes.