Tenofovir Disoproxil Fumarate in the Treatment of Parkinson's Disease

This study tests whether tenofovir disoproxil fumarate — an antiviral drug commonly used for hepatitis B — may slow or improve symptoms of Parkinson's disease. Laboratory research has suggested it may have protective effects on brain cells. **You may be eligible if...** - You have been diagnosed with Parkinson's disease at an early to moderate stage (Hoehn & Yahr scale 1 to 2.5) - Your cognitive function is at a normal or near-normal level (MMSE score of 24 or higher) **You may NOT be eligible if...** - You have been diagnosed with essential tremor, stroke, epilepsy, or other defined neurological diseases - You have had deep brain stimulation or other brain surgery - You have abnormal liver or kidney function - You have chronic hepatitis B or HIV - You have severe depression, schizophrenia, or other psychiatric conditions - You have serious heart, lung, liver, kidney, or blood disorders, or a cancer diagnosis - You are pregnant, breastfeeding, or over 65 years of age - You are allergic to the study drug Talk to your doctor to see if this trial is right for you.