Effects of cyclosporin A administration in cats.

Cyclosporin A was administered orally to 10 cats for 28 consecutive days at a dosage of 20 mg/kg body weight daily divided into 2 equal doses. Serum trough CyA concentrations ranged from 134 to 902 ng/ml with a mean of 567 +/- 249 ng/ml (means +/- SD). Immunosuppression by CyA was suggested in 5 cats by significantly depressed lymphoblast transformation responses. Various hematologic, serum chemical, and urinalysis parameters were monitored on a weekly basis in 10 cats. Serum urea nitrogen concentration increased significantly from baseline values on days 7, 14, and 21, but not on day 28. Urine concentrating ability was unimpaired. Alanine aminotransferase activity was decreased significantly from baseline values at each sample period during CyA administration. Drug-related side effects were minor; one cat developed gingival hypertrophy which regressed within 21 days of CyA withdrawal.