Felis ISSN 2398-2950

Therapeutics: immune system

Synonym(s): Immunomodulatory drug

Contributor(s): Linda Horspool, Claire Targett, Lauren Trepanier, Anna Threlfall


  • Glucocorticoids (steroids, eg prednisolone) Therapeutics: glucocorticoids remain the mainstay of immunosuppressive therapy in veterinary medicine as a result of their broad efficacy and relatively low cost. Both short-term and long-term prednisolone therapy is associated with significant risk of side-effects.
  • The response to glucocorticoids is variable within and between species. Cats require higher doses than dogs to have the same effect, and larger breed dogs tend to suffer more significant side-effects. In humans, glucocorticoid resistance is documented in up to 30% of patients, and has also been documented in veterinary patients with cancer. 
  • There are several scenarios in which an alternative immunosuppressant strategy is required, and there are now several alternative drugs available.
  • Examples of immunosuppressive agents include:
    • Azathioprine 
    • Chlorambucil 
    • Ciclosporin/Cyclosporine 
    • Cyclophosphamide 
    • (Gold salts - limited use, specific indications only, rarely used) 
    • Human intravenous immunoglobulin (hIVIg) 
    • Leflunomide 
    • Methotrexate 
    • Mycophenolate mofetil 
    • Prednisolone 
    • (Sulfasalazine -limited use, specific indications only, occasionally used for inflammatory large bowel disease in dogs) 
    • Vincristine 

Many of these drugs are not licensed in veterinary species, and licensing varies across the world. It is therefore advisable to check with the local authority prior to administration. 


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Slovak J E, Hwang J K, Rivera S M et al (2019) Pharmacokinetics of mycophenolic acid and its effect on CD4+ and CD8+ T cells after oral administration of mycophenolate mofetil to healthy cats. J Vet Int Med 33(5), 2020-2028 PubMed.
  • Slovak J E, Rivera S M, Hwang J K et al (2017) Pharmacokinetics of Mycophenolic Acid after Intravenous Administration of Mycophenolate Mofetil to Healthy Cats. J Vet Int Med 31(6) 1827-1832 PubMed.
  • Bacek L M & Macintire D K (2011) Treatment of primary immune‐mediated hemolytic anemia with mycophenolate mofetil in two cats. J Vet Emerg Crit Care 21 (1), 45-49 PubMed.  
  • Wisselink M A & Willemse T (2009) The efficacy of cyclosporine A in cats with presumed atopic dermatitis: A double blind, randomised prednisolone-controlled study. Vet J 180 (1), 55-59 PubMed.
  • Kirpensteijn J (2006) Feline injection site-associated sarcoma: Is it a reason to critically evaluate our vaccination policies? Vet Microbiol 117 (1), 59-65 PubMed.
  • Schultz R D (2006) Duration of immunity for canine and feline vaccines: a review. Vet Microbiol 117 (1), 75-79 PubMed.
  • Hanna F Y (2005) Disease modifying treatment for feline rheumatoid arthritis. Vet  Comp Orthop Traumatol18, 94-99 PubMed.
  • Gaskell R M, Gettinby G, Graham S J et al (2002) Veterinary Products Committee working group report on feline and canine vaccination. Vet Rec 150 (5), 126-134 PubMed.
  • Miller E (1997) Immunosuppression--an overview. Semin Vet Med Surg (Small Anim) 12 (3), 144-149 PubMed.
  • Miller E (1997) The use of cytotoxic agents in the treatment of immune-mediated diseases of dogs and cats. Semin Vet Med Surg (Small Anim) 12 (3), 157-160 PubMed.
  • Beale K M, Altman D, Clemmons R et al (1992) Systemic toxicosis associated with azathioprine administration in domestic cats. Am J Vet Res 53 (7), 1236-1240 PubMed.

Other sources of information