In a retrospective analysis of paediatric renal-transplant recipients receiving basiliximab, we noted significantly increased blood concentrations of cyclosporin, early cyclosporin toxicity, and a lower dose requirement within the first 10 days compared with controls. As the CD25 saturation fades at days 28-50, cyclosporin concentrations decline and 20% higher doses are required to maintain adequate trough concentrations. We suggest that an interleukin-2 receptor-mediated alteration of the cytochrome P450 system causes this systemic drug interaction and propose that the initial ciclosporin dose should be limited to 400 mg/m2 if used in combination with basiliximab.
