Case Description—An 8-year-old spayed female Yorkshire Terrier and 5-year-old castrated male West Highland White Terrier were evaluated because of cyclophosphamide intoxication subsequent to pharmacy error. Both dogs received cumulative doses of approximately 1,080 mg of cyclophosphamide/m2 after cyclophosphamide was erroneously dispensed instead of cyclosporine by different pharmacies.
Clinical Findings—Both dogs became lethargic, and 1 dog also had anorexia, vomiting, and diarrhea within 2 days after initiation of cyclophosphamide administration. The other dog developed anorexia on the seventh day after initiation of cyclophosphamide administration. The dogs were evaluated by their primary-care veterinarians 9 and 11 days after administration of the first dose of cyclophosphamide, and both had severe leukopenia and thrombocytopenia.
Treatment and Outcome—One dog was treated on an outpatient basis with broad-spectrum antimicrobials, granulocyte colony-stimulating factor, and an appetite stimulant. The other dog was more severely affected and was hospitalized for 7 days, during which it was treated with broad-spectrum antimicrobials, gastroprotectants, granulocyte colony-stimulating factor, and cryopreserved platelet and packed RBC transfusions. Both dogs fully recovered after treatment.
Clinical Relevance—This was the first report of survival for dogs with inadvertent prolonged cyclophosphamide intoxication subsequent to pharmacy error. Although the 2 dogs had similar clinical signs and clinicopathologic findings, the severity of disease and treatment required differed for each dog. Dogs can recover from prolonged cyclophosphamide intoxication provided appropriate supportive care is administered.