fenbendazole + reduced [NADPH--hemoprotein reductase] + O2 = fenbendazole S-oxide + oxidized [NADPH--hemoprotein reductase] + H2O + H(+)
fenbendazole + reduced [nadph--hemoprotein reductase] + o2 = fenbendazole s-oxide + oxidized [nadph--hemoprotein reductase] + h2o + h(+)