Intervention: Droxidopa
Trial phase: Phase 3
ATC code: C01CA27
SMILES: N[C@H](C(=O)O)[C@H](O)c1ccc(O)c(O)c1
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 81
Group description: 100 mg, oral, three times per day 200 mg, oral, three times per day 300 mg, oral, three times per day 400 mg, oral, three times per day 500 mg, oral, three times per day 600 mg, oral, three times per day

Droxidopa: 100 mg, oral, three times per day 200 mg, oral, three times per day 300 mg, oral, three times per day 400 mg, oral, three times per day 500 mg, oral, three times per day 600 mg, oral, three times per day
Eligibility criteria:
Inclusion Criteria:

To be eligible for inclusion, each patient must fulfill the following criteria:

Male or female and aged 18 years or over
Clinical diagnosis of orthostatic hypotension associated with Primary Autonomic Failure (PD, MSA and PAF), Dopamine Beta Hydroxylase Deficiency or Non-Diabetic Autonomic Neuropathies
A documented fall in systolic blood pressure of at least 20 mmHg, or in diastolic blood pressure of at least 10 mmHg, within 3 minutes after standing;
Provide written informed consent to participate in the study and understand that they may withdraw their consent at any time without prejudice to their future medical care.

Exclusion Criteria:

Currently taking ephedrine or midodrine
Patients taking ephedrine or midodrine must stop taking these drugs at least 2 days prior to their baseline visit (Visit 2).
The use of short-acting anti-hypertensive medications at bedtime is permitted.
Currently taking tri-cyclic antidepressant medication or other norepinephrine re-uptake inhibitors;
Have changed dose, frequency and or type of prescribed medication, within two weeks of study start (excluding ephedrine and midodrine)
History of more than moderate alcohol consumption
History of known or suspected drug or substance abuse
Women of childbearing potential who are not using a medically accepted contraception
For WOCP a serum beta HCG pregnancy test must be conducted at screening, and a urine pregnancy test must be conducted at baseline and study termination; the results must be negative at screening and at baseline for the patient to receive study medication.
Sexually active males whose partner is a WOCP and who do not agree to use condoms for the duration of the study and for 30 days after the last dose;
Women who are pregnant or breast feeding
Known or suspected hypersensitivity to the study medication or any of its ingredients
Pre-existing sustained severe hypertension (BP 180/110 mmHg in the sitting position)
Have atrial fibrillation or, in the investigator's opinion, have any other significant cardiac arrhythmia
Any other significant systemic, hepatic, cardiac or renal illness
Diabetes mellitus or insipidus
Have a history of closed angle glaucoma
Have a known or suspected malignancy
Have a serum creatinine level > 130 mmol/L
Patients with known gastrointestinal illness or other gastrointestinal disorder that may, in the investigator's opinion, affect the absorption of study drug
In the investigator's opinion, have clinically significant abnormalities on clinical examination or laboratory testing
In the investigator's opinion, are unable to adequately co-operate because of individual or family situation
In the investigator's opinion, are suffering from a mental disorder that interferes with the diagnosis and/or with the conduct of the study, e.g. schizophrenia, major depression, dementia
Are not able or willing to comply with the study requirements for the duration of the study
Have participated in another clinical trial with an investigational agent (including named patient or compassionate use protocol) within 4 weeks before the start of the study
Previous enrolment in the study.