Hemolytic-uremic syndrome (HUS) is a well-recognized complication of cyclos
porine (CyA) therapy. Transplant recipients with this complication are freq
uently switched to tacrolimus, although this drug has also been implicated.
We report a case of a renal transplant recipient who developed severe graf
t dysfunction due to biopsy-proven HUS after receiving CyA. Renal function
and hemolytic parameters improved with discontinuation of the drug, but the
y deteriorated again after commencement of tacrolimus 15 days later. A seco
nd transplant biopsy demonstrated fresh lesions diagnostic of HUS. Hemolyti
c parameters resolved with discontinuation of tacrolimus. This is the first
report of metachronous HUS being caused in a renal transplant by both CyA
and tacrolimus. We therefore believe that caution should be exercised when
using tacrolimus as rescue therapy in patients with CyA-induced HUS.