Flutamide and its more potent active metabolite 2-hydroxyflutamide competitively block dihydrotestosterone binding at androgen receptors, forming inactive complexes which cannot translocate into the cell nucleus. Formation of inactive receptors inhibits androgen-dependent DNA and protein synthesis, resulting in tumor cell growth arrest or transient tumor regression. (NCI04). Flutamide has been linked to numerous cases of acute liver injury, which are frequently severe and can be fatal.