Peripheral Dopamine in Postural Tachycardia Syndrome

• Status: Active, not recruiting
• Trial end date: 2021-12-01
• Target enrollment: 0
• Participant gender: All

Summary

The purpose of the proposed research is to determine how changes in kidney dopamine (DA) activity influence urinary sodium excretion. We will decrease DA activity in the kidney by inhibiting DA synthesis via carbidopa administration. We want to compare findings in normal volunteers and in patients with postural tachycardia syndrome (POTS). We will test the null hypothesis (Ho) that the effects of oral carbidopa administration on urinary sodium excretion will not differ between patients with POTS and healthy volunteers.

• Phase: Phase 2/Phase 3
• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: Vanderbilt University; Vanderbilt University Medical Center
• Treatments: Carbidopa; Dopamine; Dopamine Agents

Criteria

Inclusion Criteria:

• Patients diagnosed with POTS by the Vanderbilt Autonomic Dysfunction Center based on the following stringent criteria: 1) history of daily orthostatic symptoms for at least 6 months; 2) increase in heart rate (HR) of at least 30 bpm with standing or a standing HR of at least 120 bpm; 3) absence of orthostatic hypotension (defined as a fall in blood pressure (BP)>20/10 mm Hg); and 4) absence of conditions, such as dehydration, substantial weight loss, or systemic illnesses, that could provoke orthostatic intolerance

• Upright plasma NE at least 600 pg/mL in patients

• Non-smoking

• Free of medications with the potential to influence BP

• Able and willing to provide informed consent -

Exclusion Criteria:

• Overt cause for postural tachycardia (such as acute dehydration)

• Significant cardiovascular, pulmonary, hepatic, or hematological disease by history or screening results

• Positive urine b-hcg pregnancy test

• Evidence of cardiac structural disease (by clinical examination or prior echocardiogram)

• Hypertension defined as a BP>145/95 (off medications) or need for antihypertensive medications

• Evidence of significant conduction system delay (QRS duration >120 ms) on electrocardiogram

• Inability to give, or withdraw, informed consent