To evaluate the efficacy of a 4-week fludrocortisone (FLU) treatment on systolic blood pressure depression after 5 minutes of active orthostatism in patients with neurogenic orthostatic hypotension (HON) symptomatic, despite treatment with non-drug measures with or without midodrine.

The objective of the study is to demonstrate the efficacy of FLU on systolic blood pressure depression in patients with neurogenic orthostatic hypotension. The study is randomised versus placebo.Each patient will be followed for a maximum of 5 months, with no more than 8 visits to the investigator (V0 at Day-7, V1 at D0, V2 at D7, V3 at D+14, V4 at D+21, V5 at D+ 28, V6 at D+56 and V7 only for patients on the FLU arm at D+140.

The presence of a comparator control group with placebo permits to evaluate the efficacy and the tolerance of FLU independently of the natural evolution of the pathology, in patients benefiting from a non-drug or possibly medicated treatment (midodrine) but insufficient.

Inclusion Criteria:

• Diagnosis of orthostatic hypotension (HO), ie a blood pressure drop> 20 and / or 10 mmHg within 3 minutes after active and symptomatic lifting
• Patient suffering from a neurological disease
• orthostatic neurogenic hypotension persistent and symptomatic despite non-drug measures

Exclusion Criteria:

• Hypersensitivity to FLU or any of its excipients
• non orthostatic neurogenic hypotension
• History of proven heart failure
• History of left ventricular systolic dysfunction
• Uncompensated hypokalemia
• Patient with poorly balanced Grade 3 hypertension
• Pregnant patient at the time of inclusion
• Nursing patient