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: 22
Group description: Droxidopa 100 mg, 200 mg, 300 mg

Droxidopa: 100 mg, 200 mg and 300 mg capsules 100, 200, 300, 400, 500, 600mg TID dosing for up to 12 weeks of treatment
Eligibility criteria:
Inclusion Criteria:

1. 18 years and older and ambulatory (defined as able to walk at least 10 meters);

2. Clinical diagnosis of symptomatic orthostatic hypotension associated with Primary Autonomic Failure (PD, MSA and PAF), Dopamine Beta Hydroxylase Deficiency;

3. At the Baseline visit (Visit 2), patients must demonstrate:

a score of at least 4 or greater on the Orthostatic Hypotension Symptom Assessment (OHSA) Item #1;

a fall of at least 20 mmHg in their systolic blood pressure, within 3 minutes of standing;

4. 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:

1. Score of 23 or lower on the mini-mental state examination (MMSE);

2. Concomitant use of vasoconstricting agents for the purpose of increasing blood pressure;

Patients taking vasoconstricting agents such as ephedrine, dihydroergotamine, or midodrine must stop taking these drugs at least 2 days or 5 half-lives (whichever is longer) prior to their baseline visit (Visit 2) and throughout the duration of the study;

3. Known or suspected alcohol or substance abuse within the past 12 months (DSM-IV definition of alcohol or substance abuse);

4. Women who are pregnant or breastfeeding;

5. Women of child bearing potential (WOCP) who are not using at least one method of contraception with their partner;

6. Male patients who are sexually active with a woman of child bearing potential (WOCP) and not using at least one method of contraception;

7. Untreated closed angle glaucoma;

8. Diagnosis of hypertension that requires treatment with antihypertensive medications (short-acting antihypertensives to treat nocturnal supine HTN are allowed in this study) Any significant uncontrolled cardiac arrhythmia;

9. History of myocardial infarction, within the past 2 years;

10. Current unstable angina;

11. Congestive heart failure (NYHA Class 3 or 4);

12. History of cancer within the past 2 years other than a successfully treated, non-metastatic cutaneous squamous cell or basal cell carcinoma or cervical cancer in situ;

13. Gastrointestinal condition that may affect the absorption of study drug (e.g. ulcerative colitis, gastric bypass);

14. Any major surgical procedure within 30 days prior to the Baseline visit (Visit 2);

15. Previously treated with droxidopa within 30 days prior to the Baseline visit (Visit 2);

16. Currently receiving any other investigational drug or have received an investigational drug within 30 days prior to the Baseline visit (Visit 2);

17. Any condition or laboratory test result, which in the Investigator's judgment, might result in an increased risk to the patient, or would affect their participation in the study;

18. The Investigator has the ability to exclude a patient if for any reason they feel the subject is not a good candidate for the study or will not be able to follow study procedures.