Effects of vitamin B12, folate, and entacapone on homocysteine levels in levodopa-treated Parkinson's disease patients: A randomized controlled study.

Introduction: Previous studies have suggested a significant increase in plasma homocysteine (Hcy) levels in levodopa-treated Parkinson's disease (PD) patients, and vitamin B12 and folate supplementation may decrease Hcy levels. However, the effects of catechol-O-methyltransferase inhibitors on levodopa-induced increase in Hcy levels were conflicting. The aim of this study was to evaluate whether Hcy levels are increased in levodopa-treated PD patients and to evaluate the effects of vitamin B12 and folate or entacapone on Hcy levels in levodopa-treated PD patients.