Cyclosporine is a T-cell lymphocyte suppressor with demonstrated efficacy in steroid-refractory IBD in dogs.20 It is occasionally used to treat dermatologic conditions in cats, but its use in cats with IBD has not been reported. The
recommended dose for cats is 1-4 mg/kg orally every 12 to 24 hours (Table 3).21 Cyclosporine can cause vomiting or anorexia in some patients.
Azathioprine is a purine antagonist antimetabolite with potent immunosuppressive properties. It is routinely used for refractory
IBD in dogs. However, it is not recommended for use in cats because of the potential for fatal bone marrow toxicosis and difficulties
with accurate dosing.
Adjunctive therapies in cats with chronic diarrhea include cobalamin, pancreatic enzymes, prebiotics, probiotics, GI protectants,
and motility modifiers and may be needed in patients with the specific conditions described below or in patients with nonspecific
diarrhea in which conservative therapy is preferred.
Hypocobalaminemia is commonly documented in cats with malabsorptive or infiltrative distal small intestinal mucosal disease
and is a predictable finding in cats with exocrine pancreatic insufficiency (EPI).22,23 Treating hypocobalaminemia reduces the frequency of diarrhea and improves fecal consistency in cats with chronic enteropathies.24 All cats with serum cobalamin concentrations < 300 ng/L should receive parenteral cobalamin supplementation. Cyanocobalamin
is the generic preparation used for subcutaneous or intramuscular injection. It usually contains 1,000 µg/ml of cobalamin
in solution, making it more convenient and less irritating than B-complex preparations. The standard dosing regimen is described
in Table 4. Cobalamin supplementation is often administered long-term or until resolution of the underlying disease.