Peer-reviewed veterinary case report
Azathioprine liver toxicity risk and timing in dogs
By Wallisch, K & Trepanier, L A·Published in Journal of veterinary internal medicine·2015·Department of Medical Sciences·View original on PubMed →
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Original publication title: Incidence, timing, and risk factors of azathioprine hepatotoxicosis in dogs.
- Species:
- dog
Plain-English summary
Five dogs treated with azathioprine, a medication often used for autoimmune conditions, developed liver problems within about two weeks. The affected dogs showed a significant increase in liver enzymes, which improved after stopping or reducing the medication. German shepherds were more likely to experience these liver issues compared to other breeds. While some dogs also had low blood cell counts, these problems appeared much later in treatment. Regular monitoring of liver function is recommended for dogs on azathioprine, especially during the first month of treatment.
People also search for: dog azathioprine side effects · German shepherd liver problems · how to monitor dog liver health
Abstract
BACKGROUND: The use of azathioprine (AZA) in dogs is limited by the development of hepatotoxicosis and cytopenias. HYPOTHESIS AND OBJECTIVES: To characterize the observed incidence, timing, and risk factors for AZA hepatotoxicosis in dogs treated clinically, and to determine the relationship between the development of hepatotoxicosis and cytopenias. ANIMALS: Fifty-two dogs treated with AZA with clinical and biochemical follow-up, with a subset of 34 dogs available for determination of changes in liver enzyme activities in serum. METHODS: Retrospective medical record review, from January 2009 through December 2013. RESULTS: Hepatotoxicosis (as defined by a >2-fold increase in serum ALT) was observed in 5 of 34 dogs (15%) within a median onset of 14 days (range, 13-22 days). Dogs had a median 9-fold increase in ALT and 8-fold increase in ALP, which stabilized or resolved with drug discontinuation or dose reduction. German shepherds were significantly over-represented (3 of 5 dogs with hepatotoxicosis; P = .0017). Thrombocytopenia or neutropenia were seen in 4 of 48 dogs with CBC follow-up (8% of dogs), but occurred significantly later in treatment (median onset, 53 days; range 45-196 days) compared to hepatotoxicosis (P = .016). CONCLUSIONS AND CLINICAL IMPORTANCE: These results support the routine monitoring of liver enzymes during the first 1-4 weeks of AZA treatment in dogs, with continued monitoring of the CBC. Additional studies are warranted to characterize the apparently higher risk of AZA hepatotoxicosis in German shepherds.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/25641386/