Laboratory Monitoring of Cyclosporine Pre-dose Concentration (C0) After Kidney Transplantation in Isfahan

Background: Cyclosporine is the main immunosuppressive agent used in organ transplantation which leads to considerable improvement in graft survival. The large inter- and intra- patient variability in cyclosporine pharmacokinetics coupled with the agent’s narrow therapeutic index and adverse effects necessitate therapeutic monitoring of cyclosporine blood levels. Objective: The aim of this study was to determine the extent of variability following oral administration of cyclosporine after kidney transplantation, and provide guidelines for administration of cyclosporine in Isfahan/Iran Methods: The results of 2163 cyclosporine pre-dose blood samples obtained from 647 kidney transplant recipients (208 females, 439 males) with a median age of 34 years (range 11-54 years) were studied. Concentration of cyclosporine in the whole blood was determined by a radioimmunoassay using monoclonal antibodies specific for the drug. Statistical analyses were performed using SPSS. Results: The frequency distribution of C0 and daily oral dosage of cyclosporine exhibited wide interindividual variability. Cyclosporine oral dosage regimen ranged from 100 mg to 400 mg. Trough cyclosporine blood concentration (C0) ranged from 18 ug/l to 1400 ug/l. The results of cyclosporine whole blood levels in 56% were always below the suggested therapeutic range (less than 200 ug/l) and in 14% of the samples seemed to be associated with the occurrence of toxic side effects. There were no significant differences in the median trough levels of kidney recipients according to gender (p = 0.36). Conclusion: For long-term management of kidney transplant recipients and in order to further optimize the use of cyclosporine, it is essential to standardize laboratory monitoring and clinical investigation of this agent.