Chlorambucil is an alkylating antineoplastic medication that is used to treat many immune response disease states in animals. This medication can be very useful in treating both inflammatory bowel disease (IBD) and certain cancers like lymphosarcoma. Both conditions will present with similar clinical symptoms but a biopsy will confirm the suspicion of cancer.
Investigators have concluded that full-thickness specimens of the ileum and jejunum are best for an accurate diagnosis rather than an endoscopic biopsy. Lymphosarcoma is the most common type of hematopoietic neoplasia in cats. Chlorambucil is often paired in conjunction with a corticosteroid like prednisolone when an inadequate response is found with the corticosteroid alone. Fortunately for cats, this diagnosis has a relatively good prognosis and therapy with both chlorambucil and prednisolone has shown an average survival time of 18-24 months.
Chlorambucil is metabolized by the liver and well absorbed orally. It seems to be very well tolerated in comparison to other antineoplastic drugs. Side effects related to chlorambucil include bone marrow suppression, hepatotoxicity and GI distress. Adequate testing is recommended to monitor these potential side effects by testing CBC’s at baseline, after first month and at 3 months time. For proper handling of the drug and any elimination products from the animal, it is recommended wearing gloves. Pet owners must be stressed compliance with dosing to ensure best results in their animals.
Cat dosing of Chlorambucil
- 2mg every other day OR
- 15mg/m2 daily for 4 days ever 3 weeks
Kuipel, M., Pfent, C., Xie, Y., Xue, Y.G., et al. (2011). Diagnostic Algorithm to Differentiate Lymphoma From Inflammation in Female Small Intestinal Biopsy Samples. Veterinary Pathology, 48 (1), 212-222. https://doi.org/10.1177/0300985810389479