ABSTRACT
The work is designed to estimate in Parkinson 's disease [PD] patients the effect of levodopa treatment on plasma total homocysteine [HCY] level which is an important risk factor for atherosclerosis and also, cause neuronal death by activating apoptosis. This study included 57 PD patients in addition to 10 age and sex matched healthy participants, as control group. The patients were divided into two groups; group I [n = 43] which included those who received levodopa and group II [n = 14] which included those who didn 't receive levodopa. In this study we found elevated plasma level of total homocysteine in levodopa treated Parkinson's disease patients compared to non treated patients and control, and it was significantly positively correlated with the duration of treatment irrespective of the dose of levodopa. From this study we concluded that levodopa therapy for PD is associated with increased HCY level. This increase in HCY level accelerates the death of dopamine producing cells and impairs the function of energy producing mitochondria and increases oxidative stress. So, we recommend the prescription of folic acid which is an inexpensive and well tolerated HCY lowering therapy together with levodopa, together with catechol-O-methyl transferase inhibitor to decrease the formation of HCY from levodopa via the O-metabolization pathway