The purpose of this study is to evaluate the durability of the effectiveness and safety of a study drug called droxidopa (also known by the trade name NORTHERA(R)) in people with symptomatic Neurogenic Orthostatic Hypotension (NOH). Droxidopa is a drug that is changed in the body to a chemical called norepinephrine. Norepinephrine is a chemical in your body that is used by your nervous system to signal nerves that control blood pressure.
Droxidopa (NORTHERA(R)) has been approved in the United States (US) for the treatment of orthostatic dizziness, light-headedness or the "feeling that you are about to black out" in patients with a clinical diagnosis of symptomatic NOH due to PD, MSA, PAF, NDAN, or DBH deficiency.
The study drug that you will take if you are in this study is a capsule that contains either droxidopa or placebo (an identical-looking pill that does not contain any active drug; a placebo is sometimes called a "sugar pill"). The reason for having people take placebo in this study is to see if taking droxidopa is better than taking placebo. Be aware that this form refers to both droxidopa and placebo as "study drug". Each active capsule of study drug will contain 100 mg, 200 mg, or 300 mg droxidopa.
Matching placebo capsules will contain the same ingredients as the active capsules of study drug, except that droxidopa will be replaced by an equivalent quantity of mannitol (sugar). The study drug for the double-blind period will include matching placebo for each of the dose options. The use of droxidopa in this study is considered investigational.