Carbidopa/levodopa/entacapone: the evidence for its place in the treatment of Parkinson's disease.

Abstract

Introduction: Parkinson’s disease (PD) is a common neurodegenerative disease. In the 1960s, it was shown that the degeneration of dopamine producing neurons in the substantia nigra (SN) caused the motor features of PD. Dopamine replacement with levodopa, a dopamine precursor, resulted in remarkable benefit. Yet, the intermittent administration of levodopa is a major cause of motor complications, such as “wearing-off” of levodopa’s benefit and involuntary movements, known as dyskinesia. Therefore, agents that prolong levodopa’s half-life were employed, such as carbidopa, an aromatic amino acid decarboxylase (AADC) inhibitor, and entacapone, a catechol-O-methyltransferase (COMT) inhibitor. The combination product carbidopa/levodopa/entacapone (CLE) was approved in 2003 for the treatment of PD patients.