N,N-Bis-desethyl, N-Methyl Entacapone-d3 is the isotope analog of N,N-Bis-desethyl, N-Methyl Entacapone which is an impurity of Entacapone (E558500). The (E)-Isomer of Entacapone which is a polymorphic form A. Peripherally acting inhibitor of catechol-O-methyl transferase (COMT), an enzyme involved in the metabolism of catecholamine neurotransmitters and related drugs. Antiparkinsonian.