Veterinary Medicine - August 2008 - (Page 439)

exerting an immunosuppressive effect by inhibiting T-lymphocyte function.8 Minimal, if any, side effects are associated with trientine use in dogs, but this product may be prohibitively expensive in large-breed dogs. When treating patients with D-penicillamine or trientine, it may take many months to remove excess copper from the liver (at an approximate rate of 900 µg/g dw per year) and for improvement in ALT activity to be appreciated.6,9 Copper chelation is not necessarily a benign treatment. One report in the veterinary literature described iatrogenic copper de ciency associated with longterm copper chelation in a Bedlington terrier.9 Clinical signs associated with copper de ciency can include central TABLE 2 nervous system dysfunction, anemia, and abnormal ossi cation.5 Elemental zinc Elemental zinc induces synthesis of intestinal mucosal metallothionein, which has a high af nity for copper and, thus, binds dietary copper and limits its absorption.1 The copper bound to the intestinal mucosal metallothionein is eventually excreted in feces as enterocytes are shed.1 Elemental zinc can be supplemented in the acetate, sulfate, gluconate, or methionine forms. Zinc gluconate is the most common formulation and is available over the counter. The dosage listed in Table 2 is for elemental zinc; clients may need help in selecting an appropriate product. Zinc should be given one to two hours before a meal so the maximum amount of metallothionein will be available to bind copper. If nausea is reported, zinc may be given with a small amount of canned dog food. D-penicillamine and trientine could theoretically chelate zinc, but practically it is not a problem. Staggering the therapy should suf ce.9 Ursodiol and glucocorticoids Most of the information supporting the administration of ursodiol in patients with liver disease comes from studies in people. Ursodiol, or ursodeoxycholic acid, is a hydrophilic bile acid that shifts the bile acid pro le toward the less toxic hydrophilic forms by competing with other bile acids for ileal absorption.8 In addition, the chole- Treating Canine Copper Hepatopathy* Drug D-penicillamine (Cuprimine [Merck] 125or 250-mg capsules) Trientine (Syprine [Merck] 250-mg capsules) Zinc (elemental) Dosage 10–15 mg/kg PO every 12 hours 10–15 mg/kg PO every 12 hours 50 mg/kg PO every 12 hours Use Copper chelator (cupruretic) Copper chelator (cupruretic) Induces production of intestinal metallothionein, which binds dietary copper Hepatoprotectant and choleretic Side Effects Nausea, vomiting, anorexia, lethargy, fever, skin problems Rare Comments Thought to have some antiinﬂammatory and antiﬁbrotic activity Good for patients that do not tolerate D-penicillamine Nausea, vomiting, anorexia • Over the counter • Give one to two hours before feeding. Can help copper excretion through bile in cholestatic patients Prednisolone is preferred over prednisone in patients with liver disease. Give one to two hours before feeding because food decreases absorption. Ursodiol 15 mg/kg/day PO Rare Prednisolone 0.5–1 mg/kg/ Anti-inﬂammatory day PO tapered to every other day dose 18 mg/kg/day PO 400–500 IU/day PO Antioxidant Polyuria, polydipsia, polyphagia S-adenosylmethionine None known Vitamin E Antioxidant Rare • Over the counter • Avoid vitamin E products containing selenium. *Source: References 8 and 10. VETERINARY MEDICINE August 2008 439

Table of Contents Feed for the Digital Edition of Veterinary Medicine - August 2008

Veterinary Medicine - August 2008 Contents Editors' Note Leading Off ClinQuiz Idea Exchange Practical Matters Diagnosing and Treating Canine Copper-Associated Hepatopathies Canine and Feline Demodicosis CE Form Advertiser Index Product Preview Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - August 2008

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