Study of the Fed-Fast Pharmocokinetics and Bioequivalance of 300mg Capsules of Droxidopa

One purpose of this study is to determine if taking droxidopa after eating will have an effect on how the body processes (absorbs and eliminates) the drug in healthy elderly subjects. Another purpose of this study is to see how the body processes (absorbs and eliminates) one 300mg capsule compared to three 100mg capsules. This study will also evaluate how well the body processes (absorbs and eliminates) and tolerates droxidopa when a 300 mg capsule is given 3 times a day for a total dose of 900 mg over the course of one day. Droxidopa is used to treat low blood pressure upon standing in patients with diseases of the nervous system, to prevent low blood pressure in patients with kidney disease during hemodialysis (removal of waste products of the blood), and to treat frozen gait (walking, stepping or running) and dizziness upon standing in patients with Parkinson's disease.