A Randomized, Double-Blind, Placebo-Controlled Study of Droxidopa for Fatigue in Parkinson's Disease

Inclusion Criteria: * Diagnosis of Parkinson's Disease * Have normal kidney function (determined at screening visit by blood sample analysis), and no active medical diagnoses associated with fatigue * No orthostatic symptoms (i.e. light headedness, blurred vision, and/or muscle weakness) * No objective orthostasis (significant drop in blood pressure when standing) * No supine hypertension (high blood pressure while laying down) judged to be of clinical significance by the investigator * Well-controlled depression * Stable dopaminergic medication regimen for 6 weeks prior to screening * No concurrent use of fludrocortisone, midodrine, or other medications that may raise blood pressure * PD Fatigue Scale Score of 50 or above Exclusion Criteria: * Diagnosis of Atypical Parkinsonism (having symptoms that mimic PD without a PD diagnosis) * Prior Intolerance of droxidopa * SNRI or TCA class (both antidepressant) medications (irrespective of indication) * Use of activating agents (amantadine, modafinil, methylphenidate and related stimulants) * Significant cardiac disease history * Significant kidney disease history, or creatinine (a chemical found in the blood) greater than 1.5 mg/dl at baseline * Poorly controlled depression * Women who are pregnant or breastfeeding * Significant history of Gastro Intestinal disease that may interfere with absorption (gastric bypass, inflammatory bowel disease)