TACROLIMUS (FK506) - THE PROS AND CONS OF ITS USE AS AN IMMUNOSUPPRESSANT IN PEDIATRIC LIVER-TRANSPLANTATION

Tacrolimus (FK506) is a new immunosuppressive agent that has recently been given to recipients of liver transplants. Multicentre studies con ducted in the United States and Europe have reported that tacrolimus i s superior to cyclosporine iii preventing allograft rejection. The abs orption of tacrolimus is independent of bile, and, therefore, therapeu tic blood levels are usually achieved by taking oral preparations with in 72 hours of liver transplantation. Compared with the use of cyclosp orine, this regimen has resulted in shorter hospital stays and reduced costs. Tacrolimus does not cause hirsutism or gingival hyperplasia, w hich are common disfiguring complications of cyclosporine. Serious neu rological side effects, lymphoproliferative disorders and hypertrophic cardiomyopathy have recently been reported in children taking high do ses of tacrolimus. When lower doses of tacrolimus are used in primary immunosuppressive therapy, the incidence of neurological side effects and lymphoproliferative disorders of tacrolimus and cyclosporine have been reported to be similar. Hence, tacrolimus is a potent immunosuppr essant that has many advantages over cyclosporine but must be used cau tiously, since high doses have been associated with an increased incid ence of lymphoproliferative disorders and cardiomyopathy.