Pilot Study of Open Label Homocysteine Management Therapy in Levodopa-treated Parkinson's Disease

This pilot study is testing whether a treatment to lower homocysteine levels (an amino acid that can be elevated as a side effect of levodopa, a common Parkinson's drug) helps improve thinking, memory, and quality of life in people with Parkinson's disease who take levodopa. **You may be eligible if...** - You have been diagnosed with probable Parkinson's disease - You currently take levodopa at a dose of at least 300 mg per day - You scored at least 15 on a cognitive screening test (Montreal Cognitive Assessment) - You are 40–90 years old - Your kidneys are functioning adequately - You do not have uncontrolled high blood pressure **You may NOT be eligible if...** - You have severe cognitive impairment (score below 15 on cognitive screening) - You have significant kidney disease - You are unable to provide informed consent Talk to your doctor to see if this trial is right for you.