Reducing Falls With Varenicline in Hypocholinergic Parkinson Disease

This study tests varenicline — a medication commonly used to help people quit smoking — as a treatment to reduce falls in people with Parkinson's disease (PD) who have low levels of acetylcholine, a brain chemical that helps with balance and gait. Falls are a major cause of injury in PD. **You may be eligible if...** - You have a confirmed diagnosis of Parkinson's disease - Brain imaging shows you have low cholinergic activity in a specific brain region (occipital cortex) linked to fall risk - You have a history of falls or significant balance problems - You are willing to take varenicline and attend study visits **You may NOT be eligible if...** - Your cholinergic activity in the relevant brain region is not in the lowest range - You have a history of severe psychiatric conditions (e.g., psychosis, suicidal ideation) - You are currently taking cholinesterase inhibitors or other conflicting medications - You have severe kidney disease - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.