This a from a lab paper called Therapeutic Contraindications in Exotic Pets. This is just a short excerpt.
http://www.journals.elsevierhealth.com/periodicals/ysaep/article/S1055-937X(03)00056-2/abstract
Karen L Rosenthal, DVM, MS, Dip.ABVP
Abstract
Therapeutic drugs legally available for human use have gone through exhaustive pharacodynamic testing and clinical drug trials. Far fewer drugs have been evaluated for common companion animals such as dogs and cats, and practically none have been rigorously evaluated for the exotic patient. Much of our information on dosing, efficacy, and adverse reactions is anecdotal or based on extrapolation from other species. Very little information exists on drug-to-drug interaction in vivo. However, a few recognized therapeutic contraindications exist, and many have been well documented in the field of laboratory medicine. A common example is corticosteroid usage in laboratory rabbits. The exotic animal practitioner needs to be fully aware of these limitations and implications and be willing to perform a thorough literature search for already established information when contemplating the use of a novel drug in exotic animal species.
Rabbits and Steroids
Steroids in rabbits cause two types of adverse reactions. Corticosteroids cause a severe immune suppression and liver toxicity. Other internal organs can also be affected. This is not a new finding but has been recognized since the middle of the last century.
The rabbit is a corticosteroid-sensitive species. Therefore, even small, one-time doses can cause severe changes in rabbits. A review of these changes was reported by Borgmann and coworkers. Toxicity in rabbits was documented in lymphoid organs, the liver, and the adrenal gland.
Toxicity was caused by ocular administration of steroids. Typical hepatic changes caused by steroid administration in rabbits include lipid deposits, glycogen deposition, vacuolization, and hydropic degeneration. These changes were seen whether steroids were given orally, ocular, or subcutaneously.
The immune system is affected by steroids in a multitude of ways. Atrophy and disappearance of lymphoid tissue of Peyer’s patches is described as well as lymphoid tissue in the spleen.
Studies have directly revealed the severe damage that occurs to the rabbit liver with administration of steroids. Even with low steroid doses, biochemical evidence of hepatic destruction was demonstrated. Bile acid concentration increased remarkably with steroid administration. In this study, liver pathology included marked proliferation of cholangioles and bile ducts with mononuclear cell infiltrates in portal areas. Some of these steroid-treated rabbits also had gastric ulceration and gastritis.
Other studies looked directly at the affects of steroid-induced immunosuppression in rabbits and the rabbit’s ability to fight off infection. Numerous studies have shown that steroid immunosuppression causes a decreased survival in rabbits.
Rabbits administered corticosteroids are used as a model for studying meningitis. The steroids, even given just once, reduce the immune response, allowing better study of the effectiveness of the antibiotic.
Models of knee joint infections and the influence and effectiveness of antibiotics require the use of steroids in rabbits. Once steroids are given, increased destruction of the knee joint occurs and the antibiotics are less effective.
Another model of infection is the rabbit keratitis protocol. One dose of a steroid causes enough suppression that invasive lesions of the cornea and treatment can be thoroughly studied.
