Who is ordering all those cyclosporin concentrations and how do they use them? An audit of cyclosporin therapeutic drug monitoring.
Therapeutic drug monitoring is used for the immunosuppressant drug, cyclosporin, even though it is often unclear what concentration should be targetted. At St. Vincent's Hospital, Sydney, a polyclonal, whole blood immunoassay is used to measure cyclosporin and metabolites. The objective of the present study was to audit how the concentration results produced by the laboratory were actually used to adjust dosage. Each transplantation unit was asked about their policy for dosage adjustment and which therapeutic range was used. The audit criteria were considered to be passed if the action taken based on a concentration result was (a) predictable based solely on the concentration and its relationship to the stated therapeutic range (e.g., dosage increased if concentration was below therapeutic range) or (b) based on clinical considerations (e.g., dosage decreased because of increased serum creatinine). Data were collected for the actions taken following 347 concentration results over a 6-week period. Audit criteria were fulfilled for 246 (71%) of the results. The majority of the cyclosporin concentrations (75%) were determined for the cardiopulmonary unit; 66% of these fulfilled audit criteria. Approximately two-thirds of all the cyclosporin concentrations requested were followed up by appropriate action based on stated therapeutic ranges or documented clinical reasons.
Tett
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Department of Pharmacy, University of Sydney, Australia.
Espinos
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Weekes
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D016572:Cyclosporine / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring; D004358:Drug Therapy / Q000706:statistics & numerical data*; D016027:Heart Transplantation / Q000502:physiology; D006801:Humans; D016030:Kidney Transplantation / Q000502:physiology; D008485:Medical Audit
D016572:Cyclosporine