Changes to the prescribing recommendation for therapeutic drug monitoring of Rapamune® (sirolimus)

Wyeth would like to inform healthcare professionals that switching between platforms for therapeutic drug monitoring of sirolimus, whether between immunoassay platforms or between immunoassay and HPLC, can produce differing results that may be clinically significant. Hence, if different assays are used in monitoring a single patient without the knowledge of the prescriber, the dose of Rapamune might be adjusted improperly with potential consequences, such as allograft rejection if drug exposure is too low or toxic side effects if exposure is too high. Wyeth is working with HSA to update the prescribing recommendation for therapeutic drug monitoring of Rapamune ® (sirolimus), based on the above findings. Wyeth is also advising all healthcare professionals involved in the management of patients taking Rapamune to determine the type of assay used in their laboratory(ies) and to note any changes to the assay and corresponding reference range used. Published: 20 Jan 2010

Dear Healthcare Professional Letters