Sirolimus and nefazodone interaction in a renal transplant patient

Background and Objectives: Our case demonstrates the first report of aninteraction with sirolimus and nefazodone in a stable renal transplant patient. Nefazodonecan inhibit cytochrome P450 3A4 and may result in elevated concentrations of sirolimussince sirolimus is metabolized by cytochrome P450 3A4. Methods: A 44-year-old patient was taking nefazodone pre-transplant and post-transplant. When nefazodone was discontinued the sirolimus level was undetectable. Results: This drug interaction was not suspected because the patient was on nefazodonepre-transplant. Conclusions: It is very important to monitor the sirolimus trough level when nefazodoneis initiated, discontinued, or the dose is adjusted to prevent sirolimus subtherapeuticor supratherapeutic trough levels (AU)