THE USE OF PLASMA-LEVELS FOR FK-506 DOSING IN LIVER-GRAFTED PATIENTS

FK 506 plasma levels were analyzed in 89 liver-grafted patients under FK 506-based immunosuppression. Plasma levels were found to be influen ced by the patients' liver function: compared to patients without majo r liver dysfunction, those with cholestasis had higher plasma levels a nd these plasma levels were able to differentiate between rejection an d toxicity. In patients with stable liver function, no clear differenc e was observed with regard to the plasma levels detectable during toxi city or rejection. We conclude that plasma levels can be used to deter mine the FK 506 dose but only in patients with cholestasis (i.e., duri ng the early post-transplant course, or in patients with cholestatic r ejection). In patients with stable liver function, plasma levels are o nly of limited clinical relevance.