Drug profile

The FDA adverse-event record for Cyclophosphamide

53 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Cyclophosphamide. See the species affected, top reactions, and outcomes below.

53
adverse-event reports
28.3%
death-coded share
Dog
most-reported species
13
Death by euthanasia - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
53
Total Reports
15
Deaths Reported
28.3%
Death Rate

Active Ingredients

Cyclophosphamide

Administration Routes

UnknownOralIntravenous

Species Affected

Dog 43
Cat 10

Most Affected Breeds

Domestic Shorthair 6
Retriever - Labrador 6
Retriever - Golden 5
Beagle 3
Pit Bull 3
Cat (unknown) 2
Rottweiler 2
Terrier - Bull - American Pit 2
Cattle Dog - Australian (blue heeler, red heeler, Queensland cattledog) 2
Boxer (German Boxer) 2

Most Reported Reactions

Death by euthanasia 13
Vomiting 9
Lack of efficacy - NOS 7
Lethargy (see also Central nervous system depression in 'Neurological') 6
Fever 6
Weight loss 6
Diarrhoea 6
Anorexia 5
Decreased appetite 5
Elevated alanine aminotransferase (ALT) 5
Anaemia NOS 4
Elevated serum alkaline phosphatase (SAP) 4

Outcome Breakdown

Ongoing
20 (37.7%)
Euthanized
13 (24.5%)
Outcome Unknown
9 (17.0%)
Recovered/Normal
9 (17.0%)
Died
2 (3.8%)

Cyclophosphamide Adverse Event Insights

53 reports name Cyclophosphamide; 15 recorded a death outcome (28.3% of reported events, not a population-level mortality rate). Active ingredient: Cyclophosphamide. Administration routes: Unknown, Oral, Intravenous.

By species: Dog (43 reports), Cat (10 reports). By breed: Domestic Shorthair (6), Retriever - Labrador (6), Retriever - Golden (5).

Leading clinical signs: Death by euthanasia (13), Vomiting (9), Lack of efficacy - NOS (7), Lethargy (see also Central nervous system depression in 'Neurological') (6). Outcome, 53 coded reports: Ongoing leads at 37.7%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.