Tacrolimus can be used in refractory IBD
It is administered orally at a dose of 0.1 mg/kg body weight/day (e.g. 10mg for 100kg man)
The dose may need to be adjusted in order to achieve an optimum serum trough levels of 5–10 ng/ml
The rule of thirds seems to apply – 1/3 fail and need surgery, 1/3 develop side-effects, and 1/3 respond but not all achieve remission