Vitamins and Entacapone in Levodopa-Induced Hyperhomocysteinemia: A Randomized Controlled Study

Clinical studies addressing metabolic consequences of l-dopa treatment are of great importance to develop sophisticated therapeutic strategies for Parkinson disease (PD). Postuma et al.1 report that treatment of patients with PD with folate and vitamin B12, but not with the catechol-O-methyltransferase (COMT) inhibitor entacapone, led to a reduction of l-dopa-induced elevation of plasma homocysteine.1 It should be considered whether the study allowed a sufficient time to observe a metabolic correction and whether a longer treatment period would have produced more pronounced differences between treatment groups. It is also likely that patients who had been treated with l-dopa for a longer period of time had a more profound metabolic change requiring a longer treatment period than those who were newly started on the drug. Furthermore, we wonder whether there was a nutritional bias in the population studied, as the baseline vitamin B12 levels in all treatment groups were in the lower …