ExoticRx · exoticrx.com/drugs/cyclophosphamide
US brand names:Cytoxan
Cyclophosphamide is dosed at 200–300 mg/m2 PO q21d or 50 mg/m2 daily x4 days/week in dogs, per Plumb's Veterinary Drug Handbook, 10th ed (2023, held copy; the original seed cited the 9th, which was never consulted) — Plumb's 10th ed (held) printed p.318, Cyclophosphamide monograph spanning p.318-321; page located 2026-08-05 from the book's own running heads, verified to name the drug in its body text. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 — Plumb's Veterinary Drug Handbook, 10th ed (held), Cyclophosphamide monograph, printed p.320 (corpus PDF p.347), DOGS: "Antineoplastic agent: Often used as part of a multidrug chemotherapy protocol (eg, COP, CHOP) […]" Same monograph, printed p.318, Uses/Indications: "Most clinicians do not consider cyclophosphamide for initial use as an immunosuppressive agent for […]" [INDICATION NARROWED 2026-08-12, two readers — the immune-mediated half is contradicted by the monograph.]. Verify against current literature before clinical use.
Prodrug activated by hepatic CYP enzymes to form phosphoramide mustard, which alkylates DNA, cross-linking strands and inhibiting replication.
Sterile hemorrhagic cystitis from metabolite acrolein — concurrent furosemide/mesna and adequate hydration recommended. Myelosuppression. Handler precautions. Also used for immune-mediated diseases.
Species references:All Cat (Domestic) drugsAll Dog (Domestic) drugs
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A dog/cat sample is shown here. Cited dosing for all 2 species — reptiles, birds, pocket pets, livestock, and equine — is free on the per-species pages above. Pro adds the weight-based calculator for every species.
| Species | Route | Dose | Frequency | Evidence | Source |
|---|---|---|---|---|---|
| Dog (Domestic) | PO | 200–300 mg/m2 | q21d or 50 mg/m2 daily x4 days/week | Strong | Plumb's Veterinary Drug Handbook, 10th ed (2023, held copy; the original seed cited the 9th, which was never consulted) — Plumb's 10th ed (held) printed p.318, Cyclophosphamide monograph spanning p.318-321; page located 2026-08-05 from the book's own running heads, verified to name the drug in its body text. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 — Plumb's Veterinary Drug Handbook, 10th ed (held), Cyclophosphamide monograph, printed p.320 (corpus PDF p.347), DOGS: "Antineoplastic agent: Often used as part of a multidrug chemotherapy protocol (eg, COP, CHOP) […]" Same monograph, printed p.318, Uses/Indications: "Most clinicians do not consider cyclophosphamide for initial use as an immunosuppressive agent for […]" [INDICATION NARROWED 2026-08-12, two readers — the immune-mediated half is contradicted by the monograph.] |
| Cat (Domestic) | PO | 200–300 mg/m2 | q21d |
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| Plumb's Veterinary Drug Handbook, 10th ed (2023, held copy; the original seed cited the 9th, which was never consulted) — Plumb's 10th ed (held) printed p.318, Cyclophosphamide monograph spanning p.318-321; page located 2026-08-05 from the book's own running heads, verified to name the drug in its body text. — SOURCE EDITION: Plumb's Veterinary Drug Handbook — ISBN 9781394172207, https://openlibrary.org/isbn/9781394172207 |