Newtherapies A newimmunosuppressant: tacrolimus

Summary Tacrolimus isthenew name for theJapanese immunosuppressant drugFK506.Itblocks interleukin 2 transcription therebyinhibiting theCD4 Th-llymphocyte responsetoforeign antigens. Italso selectively inhibits cytokine secretionofIL3,IL4andinterferongamma.Itismetabolised bythe cytochrome P-450enzymesystem.The results oftwo trials indicate thatitis similarto cyclosporin inefficacy andtoxicity.