Therapeutic drug monitoring of flucytosine in a cardiac transplant patient receiving continuous veno-venous hemofiltration and intermittent hemodialysis: A case report.

Invasive candidiasis is one of the common infections in solid organ transplant recipients. Guidelines recommend echinocandins or liposomal amphotericin with consideration of flucytosine (5-fluorocytosine; 5-FC) as synergistic therapy for treatment of select deep-seated Candida infections, including complex endovascular infections. Flucytosine undergoes extensive renal elimination; however, optimal dosing in patients with renal impairment, or those requiring renal replacement therapy (RRT), is not well-established. We describe a case of a 60-year old female who underwent orthotopic heart transplant complicated by Candida parapsilosis complex fungemia with mediastinitis and development of end-stage renal disease requiring RRT. Flucytosine therapeutic drug monitoring was performed on continuous veno-venous hemofiltration (CVVH) and intermittent hemodialysis (iHD) to guide appropriate dosing. Our results support 5-FC doses of 25 mg/kg daily while undergoing CVVH with a low fluid replacement rate and 21 mg/kg post-iHD or 17 mg/kg daily while receiving thrice weekly iHD.