Drug residues in serum of dogs receiving anticancer chemotherapy

Abstract

Background: The presence of drug residues in blood samples can represent an occupational hazard. However, studies on cytotoxic drug residues in serum of dogs are lacking in veterinary oncology. Objective: To evaluate possible occupational hazards associated with handling of blood samples from dogs receiving oncolytic drugs 7 days after treatment. Animals: Twenty-seven client-owned dogs treated for lymphoma or mast cell tumors with vincristine, vinblastine, cyclophosphamide, or doxorubicin. Methods: Prospective, observational study. Serum samples were either taken 7 days after administration of vincristine, cyclophosphamide, doxorubicin (lymphoma), and vinblastine (mast cell tumor), or 1-2 days after the last concurrent oral administration of cyclophosphamide (mast cell tumor). Additionally, serum was collected within 5 minutes of treatment. Measurement of drug residues in serum was performed by liquid chromatography tandem mass spectrometry (LC/MS/MS). Results: In 33 samples collected within 5 minute of treatment, the median serum concentrations were vincristine: 37mg/L (range: 11-87mg/L), vinblastine: 13mg/L (range: 13-35mg/L), cyclophosphamide: 2,484mg/L (range: 1,209-2,778mg/L), doxorubicin: 404mg/L (range: 234-528mg/L). In 81 serum samples collected 7 days after treatment vinblastine (7mg/L) was detected in 1 sample, and cyclophosphamide (7 and 9mg/L) in 2 samples collected 1-2 days after oral administration of cyclophosphamide. Medications were not detected in any of the other samples. Conclusions and Clinical Importance: Handling of blood samples from dogs receiving oncolytic chemotherapy 7 days after treatment with vincristine, vinblastine, cyclophosphamide, and doxorubicin should not present a health hazard. © 2010 by the American College of Veterinary Internal Medicine.