NEPHROLOGY 2004; 9, 418–421 et al . Correspondence: Dr Balaji Hiremagalur, FRACP, Department of Renal Medicine, The Canberra Hospital, ACT 2606, Australia. Email: balaji.hiremagalur@act.gov.au Accepted for publication 27 August 2004. Original Article Switchover to generic cyclosporine in stable renal transplant recipients: A single unit experience GIRISH S TALAULIKAR, MARTIN P GALLAGHER, GAVIN M CARNEY, ASAD A JADEER, MICHAEL C FALK and BALAJI HIREMAGALUR Department of Renal Medicine, The Canberra Hospital, Australian Capital Territory, Australia SUMMARY: Background: The introduction of the immunosuppressant cyclosporine has significantly improved renal transplant survival. It is an expensive drug and generic alternatives may offer cost advantages. However, generic alternatives must be shown to provide equivalent therapeutic efficacy and safety. This study reports our experience of a switch from the microemulsion formulation of cyclosporine, Neoral (Novartis), to the generic equivalent, Cysporin (Mayne Pharma). Method: A two-period, single-sequence, cross-over study was done to compare cyclosporine blood levels and the area under the curve (AUC) of Neoral with Cysporin 2 weeks after a 1:1 dose switch. cyclosporine blood levels were measured at time points 0, 2, 4 and 8 h (C0, C2, C4, C8) after the switch. The cyclosporine AUC at 0–4 h and 0–12 h were calculated using the trapezoidal method. The two formulations were considered to result in equivalent blood levels if the 95% confidence interval (CI) of the ratio of the two levels was within 0.8–1.25. Results and Conclusion: A total of 38 stable renal transplant patients aged 49.79 ± 11.38 years (mean ± SD), who were 7.84 ± 3.97 years postrenal transplantation, were studied. The Neoral dose at the time of the switch was 2.38 ± 1.21 mg per kg bodyweight. At all measured time points the 95% CI for the cyclosporine drug level ratio was between 0.9 and 1.15. There were no significant adverse events during the period of study. We conclude that the generic formulation of cylosporin, Cysporin, after a 1:1 switch from Neoral results in equivalent blood levels in stable renal transplant recipients. After switchover cyclosporine levels at C0 or C2 can continue to be monitored as per the institution’s current monitoring practice. KEY WORDS: bioequivalence, cyclosporine, generic medications, pharmacokinetics, renal transplant. INTRODUCTION The use of generic formulations is widespread in the therapeutic management of patients and can signifi- cantly contribute to cost savings. In transplantation, however, variations in drug pharmacokinetics can have significant adverse outcomes and clinicians are cautious in the use of generic equivalents. Generic equivalents of prednisolone and azathioprine have been available since the early 1960s and 1996, respectively. Generic equivalents of cyclosporine (CyA) microemulsion have become available recently. Although the use of generic forms of CyA has been reported in North America and Asia, it has not found acceptance in Australia. 1 The Australian Therapeutics and Goods Administration (TGA) recently approved one such colloidal dispersion formulation of CyA (Cysporin, Mayne Pharma, Melbourne, Vic., Australia) as being bioequivalent to the reference microemulsion formulation (Neoral, Novartis Pharmaceuticals Austra- lia, North Ryde, NSW, Australia) based on studies done in healthy volunteers. This study aims to compare CyA blood levels at various time points and the area under the curve (AUC) of this new formulation with the existing proprietary formulation at equivalent doses in stable Australian renal transplant recipients.