The role of tacrolimus (FK506)-based immunosuppression on bone mineral density and bone turnover after cardiac transplantation: a prospective, longitudinal, randomized, double-blind trial with calcitriol.

Background: Tacrolimus (FK506) is a new immunosuppressive drug in organ transplantation that has demonstrated experimentally to be more deleterious on bone mineral metabolism than cyclosporine. The purpose of this clinical study was to evaluate the effects of a tacrolimus-based immunosuppression on the skeleton and to investigate in a prospective, longitudinal, randomized, double-blind, study the effect of 0.25 microg calcitriol (1,25-dihydroxyvitamin D3) versus placebo in the prevention of bone loss and fracture rate after heart transplantion (HTx).