Phase 3 N=28 Randomized Single-blind Other

Peripheral Dopamine in Postural Tachycardia Syndrome

Postural Tachycardia Syndrome · Orthostatic Intolerance

Bottom Line

View on ClinicalTrials.gov: NCT00685919 ↗

Enrolled (actual)

Serious AEs

0.0%

Results posted

Sep 2021

Primary outcome: Primary: 24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine — 140; 132; 137; 154 Milliequivalents per gram (mEq/g)

Study Design & Population

Study type: Interventional
Phase: Phase 3
Interventions: Carbidopa (Drug); Placebo (Drug)
Age: Adult · 18+ yrs
Sex: All
Sponsor: Vanderbilt University
Primary completion: Jul 2020

Outcome Measures

Outcome	Result	p-value
PRIMARY 24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine	140; 132; 137; 154	—
SECONDARY Systolic Blood Pressure Measured at 8 Hours After the Last Dose of Placebo or Carbidopa	103; 101; 102; 101	—
SECONDARY Plasma Catecholamines (Norepinephrine) After the Last Dose of Placebo or Carbidopa	150; 181; 278; 245	—
SECONDARY Plasma Catecholamines (DOPA) After the Last Dose of Placebo or Carbidopa	1813; 20297; 2104; 25680	—
SECONDARY 24 Hour Urinary Catecholamine (DOPA) Excretion During Treatment Normalized to Creatinine	0.024; 0.283; 0.026; 0.385	—
SECONDARY 24 Hour Urinary Catecholamine (Dopamine) Excretion During Treatment Normalized to Creatinine	0.208; 0.035; 0.24; 0.038	—
SECONDARY Supine Plasma Renin Activity 2 Hours After the Last Dose of Placebo or Carbidopa	1.153; 1.033; 1.544; 1.878	—
SECONDARY Plasma Sodium After the Last Dose of Placebo or Carbidopa	138; 138; 139; 138	—

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.

Eligibility 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

View full record on ClinicalTrials.gov →

Data sourced from ClinicalTrials.gov (NCT00685919). Outcome figures and adverse-event rates are extracted automatically from the registry's posted results and are provided for clinician reference, not as a substitute for the primary publication.