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Cyclophosphamide

Prescription

Alkylating agent — antineoplastic / Immunosuppressant

Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team

Species

Dog, Cat

Brands

3 available

Interactions

3 documented

Formulations

Mechanism of action

Prodrug metabolized by hepatic P450 to active phosphoramide mustard, which cross-links DNA; also immunosuppressive via lymphocyte depletion

At a glance

Class

Alkylating agent — antineoplastic / Immunosuppressant

Schedule

Prescription

Storage

Store below 25°C; handle with gloves (cytotoxic); reconstituted solution stable 24h at room temp

Dosing

🐕

Dog

Lymphoma (CHOP protocol) / IMHA / Immune-mediated disease

Dose

200–300 mg/m²

Route

PO, IV

Frequency

Every 2–3 weeks (oncology); daily low-dose for immunosuppression

Max dose

500 mg

Duration: Per protocol; typically 4–6 cycles for lymphoma

🐈

Cat

Lymphoma / Immune-mediated disease

Dose

200–300 mg/m²

Route

PO, IV

Frequency

Every 2–3 weeks

Max dose

200 mg

Duration: Per oncology protocol

Educational reference only

This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Formulations

💊

Tablet — 1

Strength

50mg

Available in India

💉

Injection — 2

Strength

200mg vial

Available in India

Strength

500mg vial

Available in India

Storage

Store below 25°C; handle with gloves (cytotoxic); reconstituted solution stable 24h at room temp

Safety

Absolute contraindications — do not use

Severe bone marrow suppression
Active urinary tract infection
Sterile hemorrhagic cystitis risk

Adverse effects

Common

Myelosuppression (nadir 7–14 days)

GI upset

Alopecia

Serious

Sterile hemorrhagic cystitis

Severe neutropenia/sepsis

Cardiotoxicity (rare)

Monitoring parameters

CBC (day 7 and 14 post-dose)UrinalysisEncourage frequent urination (furosemide co-administration for cystitis prevention)

Educational reference only

Interactions

Major — 3

Furosemide

major

Furosemide inhibits renal excretion of cyclophosphamide metabolites, increasing risk of hemorrhagic cystitis

Management: Avoid concurrent use. Ensure adequate hydration and frequent voiding during cyclophosphamide therapy.

Doxorubicin

major

Both are cardiotoxic; combined use increases risk of cumulative cardiomyopathy

Management: Monitor cardiac function with echocardiography. Limit cumulative doxorubicin dose to 180-240 mg/m² in dogs.

Chloramphenicol

major

Chloramphenicol inhibits hepatic CYP enzymes required to activate cyclophosphamide prodrug, reducing its antineoplastic efficacy.

Management: Avoid concurrent use. Use alternative antibiotic during cyclophosphamide chemotherapy.

Educational reference only

Brands

International

Cytoxan

Baxter

India

Endoxan

Baxter India

Cycloxan

Cadila

FAQs

Frequently asked questions

›What is Cyclophosphamide?

Cyclophosphamide is a alkylating agent — antineoplastic / immunosuppressant used in pets. Prodrug metabolized by hepatic P450 to active phosphoramide mustard, which cross-links DNA; also immunosuppressive via lymphocyte depletion

›What is Cyclophosphamide used for in pets?

Cyclophosphamide is used in veterinary medicine for: Lymphoma (CHOP protocol) / IMHA / Immune-mediated disease; Lymphoma / Immune-mediated disease.

›What is the Cyclophosphamide dose for dogs?

For dogs, Cyclophosphamide is typically dosed as follows — Lymphoma (CHOP protocol) / IMHA / Immune-mediated disease: 200–300 mg/m² PO/IV Every 2–3 weeks (oncology); daily low-dose for immunosuppression. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What is the Cyclophosphamide dose for cats?

For cats, Cyclophosphamide is typically dosed as follows — Lymphoma / Immune-mediated disease: 200–300 mg/m² PO/IV Every 2–3 weeks. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.

›What are the side effects of Cyclophosphamide?

Common: Myelosuppression (nadir 7–14 days), GI upset, Alopecia. Serious (call your vet immediately): Sterile hemorrhagic cystitis, Severe neutropenia/sepsis, Cardiotoxicity (rare).

›Does Cyclophosphamide need a prescription?

Yes. Cyclophosphamide is a prescription medication and should only be administered under veterinary supervision.

›When should Cyclophosphamide not be used?

Do not use Cyclophosphamide if: Severe bone marrow suppression; Active urinary tract infection.

Educational reference only