The advent of potent immunosuppressive drugs to prevent rejection has led to a phenomenal improvement in renal transplant results increasing spectacularly the number of transplant recipients to arrive in the transplant clinic who remain for many years. This has engendered a series of questions about the most appropriate cyclosporine dosing for these patients that prevents rejection while avoiding toxicity. Three separate issues were analyzed: the most appropriate combination strategy with cyclosporine as a base "double" or "triple" therapy; the possibility of conversion from regimens containing cyclosporine to those devoid of it; and the optimal cyclosporine dose for a maintenance regimen. A meta-analysis of seven individual prospective and randomized trials of double versus triple therapy encompassing 1,080 patients revealed no statistical difference between the two regimens in terms of graft survival at 1 or 5 yr, patient survival, the rejection rate per patient, or the infection rate. In an analysis of 17 separate studies in which conversion away from cyclosporine was attempted, in 629 individuals with 702 individuals left on cyclosporine as controls, a significant risk of acute rejection (P < 0.001) was found in the withdrawn group without evidence of improved graft survival. Certain factors such as previous rejection, race, and degree of reactivity predicted even more rejection in the withdrawn group. Analyzing six separate studies of renal transplant recipients maintained on cyclosporine for up to 5 yr with renal functional stability, one can conclude that a dose of approximately 4.0 mg/kg per day is optimal. Because of variant pharmacokinetics or concomitant medicines, blood levels can confirm a therapeutic concentration with this target dose.(ABSTRACT TRUNCATED AT 250 WORDS)