Cyclosporin A: analytical methodology and factors affecting therapeutic drug monitoring

The majority of centres measuring cyclosporine have followed the advice of previous consensus meetings. Although most measurements are made using assays with a high specificity for the parent compound, there are still some between-method differences that can be attributed to methodological variables, such as antibody specificity and assay calibration. With experience of cyclosporine therapeutic drug monitoring (TDM) now spanning 15 years, it would be reasonable to infer that the subject is incapable of growth. However, continued interest in the pharmacokinetics of cyclosporine, the introduction of a new formulation of the drug, and the development of new immunosuppressive agents all combine to emphasise the still incomplete extent of our knowledge in this field.