VETINUITY
Cyclophosphamide dosing ranges from 10 mg/m2 PO q48h for canine metronomic therapy to 200-250 mg/m2 PO for pulse lymphoma protocols in dogs and cats.
For canine metronomic therapy, cyclophosphamide is administered at 10 mg/m2 PO every 48 hours, while pulse chemotherapeutic protocols in dogs and cats utilize 200 to 250 mg/m2 PO per cycle per the Vetinuity cyclophosphamide dose calculator below.
| Indication | Species | Dose | Route and frequency |
|---|---|---|---|
| Metronomic therapy for soft tissue sarcoma | Dog | 10 mg/m2 | PO q48h |
| Pulse dosing in CHOP or COP protocols | Dog | 200-250 mg/m2 | PO Single dose per 2-3 week cycle |
| Pulse dosing in COP, CHOP, or COVP lymphoma protocols | Cat | 200 mg/m2 | PO Single dose per 2-3 week cycle |
| Myeloma-related disorders with prednisolone | Cat | 200 mg/m2 | PO Single dose per 2-3 week cycle |
Sterile hemorrhagic cystitis occurs more frequently with metronomic protocols than pulse dosing; concurrent furosemide at 1 mg/kg reduces SHC incidence during pulse dosing.
Cyclophosphamide combined with corticosteroids yields high overall response rates (83% to 90%) for feline myeloma-related disorders and is well tolerated in feline COP or CHOP lymphoma regimens.
In dogs with soft tissue sarcomas, continuous metronomic administration of cyclophosphamide at 10 mg/m2 PO combined with piroxicam at 0.3 mg/kg PO significantly prolongs the disease-free interval after incomplete surgical resection. In canine chemotherapy-naive B-cell multicentric lymphoma, cyclophosphamide combined with prednisolone achieved an overall response rate of 84 percent. In canine splenic hemangiosarcoma, adjuvant doxorubicin and cyclophosphamide combination protocols or metronomic therapy extend early survival times post-splenectomy.
In feline oncology, cyclophosphamide forms a core component of COP, CHOP, and COVP protocols for alimentary and renal lymphoma. For feline myeloma-related disorders, first-line treatment with cyclophosphamide and prednisolone yields overall response rates of 83 to 90 percent with lower toxicity rates than melphalan.
Sterile hemorrhagic cystitis (SHC), bone marrow suppression, and gastrointestinal toxicity represent the primary dose-limiting adverse effects of cyclophosphamide in canine patients. Dogs undergoing continuous metronomic dosing demonstrate a significantly higher rate of SHC (84.2% of SHC cases) compared to those receiving pulse dosing (15.8% of SHC cases), associated with higher cumulative dosages. Conversely, bone marrow suppression and gastrointestinal side effects occur predominantly with pulse chemotherapy regimens.
In cats, cyclophosphamide protocols are generally well tolerated, with mild gastrointestinal adverse events like grade 1 or 2 vomiting and manageable hematologic toxicities being most common.
Concurrent administration of oral furosemide at a dose of 1 mg/kg alongside maximum tolerated pulse doses of cyclophosphamide (median dose 239.3 mg/m2 PO) effectively limits the incidence of sterile hemorrhagic cystitis in dogs to 2.46 percent. Every-other-day administration of metronomic cyclophosphamide improves patient tolerance compared to daily dosing. Baseline complete blood counts, urinalysis, and close monitoring for dysuria or hematuria are recommended during therapy.
Vetinuity is a clinical assistant built by Brian Toncray, an emergency veterinarian, to provide evidence-based treatment options with citations, precise dose math, and medical record summaries.
Calcium gluconate is administered intravenously at 14 to 42 mg/kg in dogs and cats to treat acute ionized hypocalcemia and severe hyperkalemia.
Mitoxantrone is dosed at 5 mg/m2 IV q21d in dogs and 2.5 to 6.5 mg/m2 IV q21d in cats for lymphoma, carcinoma, and mesothelioma.
L-asparaginase is dosed at 400 IU/kg IM or SQ in dogs and cats for lymphoma protocol induction, rescue, or combination protocols.
Hypertonic saline is dosed at 4 mL/kg IV for canine intracranial hypertension and 3.3 mL/kg IV over 15 minutes for feline volume expansion.
Metronomic dosing uses continuous low doses such as 10 mg/m2 PO every 48 hours to inhibit angiogenesis, whereas pulse dosing uses high single doses of 200 to 250 mg/m2 PO per cycle; metronomic protocols carry a higher risk of sterile hemorrhagic cystitis while pulse protocols are more likely to cause myelosuppression and gastrointestinal side effects.
Cyclophosphamide combined with prednisolone is an effective first-line option for feline myeloma-related disorders, achieving overall response rates between 83 percent and 90 percent with fewer treatment-discontinuation toxicities compared to melphalan.
Co-administering oral furosemide at 1 mg/kg with pulse cyclophosphamide maintains a low SHC incidence of 2.46 percent, while using every-other-day schedules instead of daily administration improves tolerance during metronomic regimens.
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