Data fra in vitro forsøg, hvor der er anvendt humant levermikrosomalt materiale, indikerer at entakapon hæmmer cytokrom P450 2C9 (IC50 ~ 4 μM).
Data from in vitro studies using human liver microsomal preparations indicate that entacapone inhibits cytochrome P450 2C9 (IC50 ∼ 4 µM).