Intestinal Levodopa + Entacapone Therapy (Lecigon®) to Counteract Dopaminergic Desensitization and Neuropsychiatric Complications in Parkinson's Disease

This study is testing a gel-form medication (Lecigon) delivered directly into the small intestine for people with Parkinson's disease who experience both movement and psychiatric side effects from their current dopamine medications. The goal is to see whether this delivery method can reduce these fluctuating symptoms. **You may be eligible if...** - You are between 18 and 75 years old - You have been diagnosed with Parkinson's disease for at least 5 years, with disease onset before age 65 - You are currently taking levodopa and a dopamine agonist (non-ergot type) - You experience motor fluctuations (times when your medication wears off) AND psychiatric/mood fluctuations tied to your medication - You show signs of behavioral problems related to too much dopamine (such as compulsive behaviors or mild psychosis) but still have insight into your condition - Your oral medications have been stable for the past 4 weeks - You are willing to use reliable contraception if applicable **You may NOT be eligible if...** - You are pregnant or breastfeeding - You have severe cognitive impairment (low score on memory tests) - You have active psychosis without self-awareness, severe depression, or active suicidality - You have already had a device implanted for Parkinson's treatment (e.g., deep brain stimulation or intestinal drug pump) - You have a history of allergic reaction to the study drug - You have untreated cancer or contraindications to intestinal tube placement - You participated in another clinical trial in the past 3 months Talk to your doctor to see if this trial is right for you.