Cyclosporine monitoring.

Cyclosporine is an important immunosuppressive agent in organ and bone marrow transplantation. The pharmacokinetics of cyclosporine are quite complex and are complicated by the availability of two assay systems that yield differing results. This article summarizes the views from two major solid organ transplant centers and one bone marrow transplant center on important cyclosporine monitoring questions. A general consensus exists in the four areas discussed that: cyclosporine concentrations must be monitored due in part to the extreme variability in kinetics, either blood or plasma can be used in monitoring programs, the radioimmunoassay or high pressure liquid chromatography can be used in routine monitoring, and the interpretation of cyclosporine concentrations must be performed in relation to patient variables that affect drug response and toxicity.