Azathioprine
Veterinary Compounding Medication – Customized for Dogs
Quick Reference
Basic Information
Azathioprine is a purine-antagonist anti-metabolite that suppresses immune system activity by interfering with DNA synthesis. It inhibits the proliferation of immune cells, particularly T-lymphocytes and B-lymphocytes, thereby reducing autoantibody production and mitigating autoimmune reactions.
After oral administration, azathioprine is absorbed through the gastrointestinal tract and converted into 6-mercaptopurine. It is metabolized in the liver and excreted primarily by the kidneys. The enzyme thiopurine methyltransferase (TMPT) plays a key role in determining both the drug’s efficacy and potential toxicity.
Applications and Administration
Applications: Azathioprine is primarily used to treat autoimmune diseases such as immune-mediated hemolytic anemia (IMHA), inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), and autoimmune skin conditions. It is often used alongside corticosteroids to reduce steroid dependency and side effects. The onset of therapeutic action is gradual, taking several weeks to achieve full effect.
Administration: This medication is best administered with food to minimize gastrointestinal irritation. Dosing frequency and duration are determined by the veterinarian based on response and blood test results.
Side Effects
Common adverse effects include gastrointestinal disturbances such as vomiting, diarrhea, and loss of appetite. More serious complications include bone marrow suppression (causing anemia, leukopenia, or thrombocytopenia), hepatotoxicity, and pancreatitis. Because it suppresses the immune system, there is an increased risk of infections and potential for neoplasia with long-term use.
Precautions
Regular blood monitoring is essential to assess liver enzymes, white and red blood cell counts, and platelet levels. Azathioprine should be used with extreme caution in dogs with pre-existing liver disease or impaired hepatic function. It is contraindicated in pregnant or lactating animals due to the risk of teratogenicity and other reproductive harm.
Drug Interactions
Caution is required when azathioprine is used with other immunosuppressants or drugs metabolized via similar hepatic pathways, such as allopurinol or ACE inhibitors, as these can increase toxicity risks. It may also interact with anticoagulants like warfarin, potentially necessitating dose adjustments.
Overdose
Overdose may cause severe bone marrow suppression, gastrointestinal upset, and hepatotoxicity. Immediate veterinary care is essential. Treatment may involve inducing emesis if ingestion is recent, administering activated charcoal, and providing supportive therapy including IV fluids and close monitoring of blood cell counts.
Custom Veterinary Compounding for Azathioprine
Rock Ridge Pharmacy provides customized veterinary formulations of Azathioprine for dogs requiring precision immunosuppressive therapy. Contact our compounding specialists to learn more about tailored dosing, delivery forms, and monitoring recommendations.
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