Following solid organ transplantation, patients receive individualised multi-drug immunosuppressive therapy, usually a combination of a Calcineurin inhibitor (Cyclosporine or Tacrolimus), a DNA synthesis inhibitor (Mycophenolic Acid) and/or an mTOR inhibitor (Everolimus or Sirolimus).
In addition to the classical assessment of the patient, one of the tools that transplant clinicians use as a guide to dose adjustment is the measurement of the drug concentrations in blood. This process is known as Immunosuppressive Drug Monitoring (ISD).
Although the current immunosuppressive drugs are effective in preventing acute rejection, most patients experience at least some adverse effects. Inadequate low therapeutic levels may lead to acute rejection, whereas very high levels are more likely to be associated with nephrotoxicity.