Hyperhomocysteinemia recurrence in levodopa-treated Parkinson's disease patients

Background: Patients with Parkinson’s disease (PD) and chronically treated with L‐DOPA exhibit, in a percentage of 10–30%, supra‐physiological levels of plasma total homocysteinemia (tHcy). In this study, we have investigated, in a group of hyper‐homocysteinemic PD patients, the time of hyper‐tHcy recurrence after discontinuation of 1‐month folate supplementation given to normalize plasma tHcy levels. Methods: Plasma tHcy, cobalamin and folate were assayed before and after 1‐month folate supplementation (5 mg/day), and after 2 and 4 months after folate discontinuation in 29 PD patients (16M/13F, mean age 69.4 ± 6.9 years) stabilized on a mean L‐DOPA dose of 509.4 ± 312.1 mg/day. Results: After folate supplementation, plasma tHcy levels fell within the normal range in all patients. At the 2‐month control after folate discontinuation, plasma tHcy remained within physiological values in 25 out of 29 patients. Conversely, 4 months after folate discontinuation, all patients exhibited hyper‐tHcy. Conclusions: One‐month intake of 5 mg/day folate normalizes plasma tHcy levels in all hyper‐homocysteinemic PD patients. Following folate discontinuation, hyper‐tHcy recurs in all patients within 4 months. Knowledge of this time interval is useful to optimize pulses of folate therapy in hyper‐homocysteinemic patients with PD.