Orthostatic Intolerance, Postural Tachycardia Syndrome
Conditions
Keywords
Dopamine, Natriuresis, Catecholamines
Brief 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.
Detailed description
We will determine whether inhibition of renal dopamine formation by carbidopa administration leads to a decrease in urinary excretion of dopamine and sodium and whether the response differs in POTS and control populations. Carbidopa effects will be compared to those of a matching placebo, and the sequence of treatments (carbidopa before placebo or placebo before carbidopa) will be randomized. Each subject will undergo a complete history and physical examination, including an electrocardiogram (EKG). * After achieving sodium balance on a 200 mEq/day sodium diet, subjects will collect urine over 24hr for baseline assessment of sodium and catecholamines. * On this day, the subjects will be admitted to the CRC. * An 18 gauge intravenous catheter will be inserted in order to draw blood. * The subjects will fast from 7 pm until after the next morning's testing. * In the morning, while still supine after the overnight sleep, heart rate and blood pressure will be recorded, and blood will be drawn. The subjects will then stand for 10 minutes. Heart rate and blood pressure will be measured at intervals, and an upright blood sample will be collected. * The subjects will be asked to collect their urine to end the 24hr urine collection. Another 24hr urine collection will be started. * Treatment A (Carbidopa 200mg or placebo) will be given orally following the void, at approximately 7 am. Additional doses will be taken every 6 hours with the last dose at 7 am the following morning. * Subjects will be free to follow their normal routine during the day until returning to the CRC for the night. However, they will need to consume the 200 mEq/day study diet for each meal, collect all urine, and take study medication on schedule * After returning to the CRC, the subjects will fast after 7 pm. * In the morning, supine and standing heart rate and blood pressure will be recorded, and the subjects will be asked to collect their urine to end the 24hr urine collection. * The final dose of study medication (Carbidopa 200mg or placebo) will be given orally following the void, at approximately 7 am. * Supine heart rate and blood pressure will be measured and supine blood samples will be collected hourly for 4 hours after the treatment and at 8 hours after the treatment. Subjects must rest supine for at least 30 minutes before each blood draw. * At 2 hours after treatment, subjects will stand for 10 minutes for upright blood pressure and heart rate measurements and collection of an upright blood sample, as described above. Participants will be asked to rate the severity of common orthostatic symptoms while supine and upright. * Urine will be collected for two 4-hour periods after treatment and from 8 hours to 24 hours after treatment. * Fixed-sodium study diet will be provided after the 4-hour measurements and in the evening. After at least a 1 day washout period, the study will be repeated with Treatment B
Interventions
DRUGCarbidopa
200 mg every 6 hours for 5 doses given orally
DRUGPlacebo
every 6 hours for 5 doses, given orally, and matching Carbidopa
Sponsors
Vanderbilt University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 60 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine | Immediately before the 1st dose of placebo or carbidopa to immediately before the 5th dose (approximately 24 hours) | Urine was collected for 24hr during treatment. Urinary volume was measured and the urine was analyzed for sodium and creatinine concentrations. Total amounts of sodium and creatinine excreted over the 24 hr were calculated and results expressed as ratio of sodium:creatinine. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Plasma Catecholamines (Norepinephrine) After the Last Dose of Placebo or Carbidopa | 8 hours after the last dose of placebo or carbidopa | Blood samples were collected while resting supine for at least 30 minutes and 2 to 4 hours after lunch. For catecholamine measurements, blood was collected in chilled vacuum tubes with EDTA. Plasma was separated and stored with added reduced glutathione (Amersham International PLC) at -70°C until the assay. Plasma catecholamines were measured by a method that involves batch alumina extraction followed by high-performance liquid chromatography (HPLC) for separation with electrochemical detection and quantification. |
| Plasma Catecholamines (DOPA) After the Last Dose of Placebo or Carbidopa | 8 hours after the last dose of placebo or carbidopa | Blood samples were collected while resting supine for at least 30 minutes and 2 to 4 hours after lunch. For catecholamine measurements, blood was collected in chilled vacuum tubes with EDTA. Plasma was separated and stored with added reduced glutathione (Amersham International PLC) at -70°C until the assay. Plasma catecholamines were measured by a method that involves batch alumina extraction followed by high-performance liquid chromatography (HPLC) for separation with electrochemical detection and quantification. |
| 24 Hour Urinary Catecholamine (DOPA) Excretion During Treatment Normalized to Creatinine | Immediately before the 1st dose of Placebo or Carbidopa and ending immediately before the last dose (approximately 24 hours) | Urine was collected over 24 hours during treatment. The urinary volume was measured and the urine was analyzed for creatinine and catecholamines. Total amounts of creatinine and catecholamines were calculated and the results are expressed as catecholamine:creatinine. |
| Systolic Blood Pressure Measured at 8 Hours After the Last Dose of Placebo or Carbidopa | 8 hours after the last dose of placebo or carbidopa | Systolic blood pressure was measured once using a Dinamap non-invasive oscillometric blood pressure monitor, 2-4 hours after lunch and after at least 30 minutes of resting supine. |
| Supine Plasma Renin Activity 2 Hours After the Last Dose of Placebo or Carbidopa | 2 hours after the last dose of placebo or carbidopa | Blood samples were collected while resting supine for at least 30 minutes and 1 1/2 to 2 hours after breakfast. Samples were processed and sent to the Vanderbilt Clinic Laboratory for assay. |
| Plasma Sodium After the Last Dose of Placebo or Carbidopa | 8 hours after the last dose of placebo or carbidopa | Blood samples were collected while resting supine for at least 30 minutes and 2 to 4 hours after lunch. Samples were processed and sent to the Vanderbilt Clinical Laboratory for assay. |
| 24 Hour Urinary Catecholamine (Dopamine) Excretion During Treatment Normalized to Creatinine | Immediately before the 1st dose of Placebo or Carbidopa and ending immediately before the last dose (approximately 24 hours) | Urine was collected over 24 hours during treatment. The urinary volume was measured and the urine was analyzed for creatinine and catecholamines. Total amounts of creatinine and catecholamines were calculated and the results are expressed as catecholamine:creatinine. |
Countries
United States
Participant flow
Pre-assignment details
* Healthy Participants Group: 21 healthy controls enrolled. 3 withdrew prior to randomization. 1 screen failed. 17 healthy participants were randomized. 1 participant was withdrawn due to orthostatic symptoms during baseline testing * Postural Tachycardia Syndrome (POTS) Group: 11 POTS participants were randomized. 1 participant withdrew after the 1st dose of the intervention (placebo).
Participants by arm
| Arm | Count |
|---|---|
| Healthy Participants-Placebo Then Carbidopa Placebo every 6 hours for 5 doses followed by Carbidopa 200 mg every 6 hours orally for 5 doses | 8 |
| Healthy Participants-Carbidopa Then Placebo Carbidopa 200 mg every 6 hours for 5 doses followed by Placebo given orally every 6 hours for 5 doses | 8 |
| Patients With POTS-Placebo Then Carbidopa Placebo every 6 hours for 5 doses followed by Carbidopa 200 mg every 6 hours orally for 5 doses | 7 |
| POTS-Carbidopa Then Placebo Carbidopa 200 mg every 6 hours for 5 doses followed by Placebo given orally every 6 hours for 5 doses | 3 |
| Total | 26 |
Withdrawals & dropouts
| Period | Reason | FG000 | FG001 | FG002 | FG003 |
|---|---|---|---|---|---|
| Overall Study | Physician Decision | 1 | 0 | 0 | 0 |
| Overall Study | Withdrawal by Subject | 0 | 0 | 1 | 0 |
Baseline characteristics
| Characteristic | Healthy Participants-Placebo Then Carbidopa | Total | POTS-Carbidopa Then Placebo | Patients With POTS-Placebo Then Carbidopa | Healthy Participants-Carbidopa Then Placebo |
|---|---|---|---|---|---|
| Age, Continuous | 34 years STANDARD_DEVIATION 11 | 32.8 years STANDARD_DEVIATION 9.5 | 37 years STANDARD_DEVIATION 3 | 31 years STANDARD_DEVIATION 10 | 32 years STANDARD_DEVIATION 10 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 8 Participants | 26 Participants | 3 Participants | 7 Participants | 8 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Black or African American | 0 Participants | 1 Participants | 0 Participants | 0 Participants | 1 Participants |
| Race (NIH/OMB) More than one race | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants | 0 Participants | 0 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) White | 8 Participants | 25 Participants | 3 Participants | 7 Participants | 7 Participants |
| Region of Enrollment United States | 8 participants | 26 participants | 3 participants | 7 participants | 8 participants |
| Sex: Female, Male Female | 8 Participants | 25 Participants | 3 Participants | 7 Participants | 7 Participants |
| Sex: Female, Male Male | 0 Participants | 1 Participants | 0 Participants | 0 Participants | 1 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 17 | 0 / 17 | 0 / 11 | 0 / 11 |
| other Total, other adverse events | 1 / 17 | 1 / 17 | 2 / 11 | 0 / 11 |
| serious Total, serious adverse events | 0 / 17 | 0 / 17 | 0 / 11 | 0 / 11 |
Outcome results
Primary
24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine
Urine was collected for 24hr during treatment. Urinary volume was measured and the urine was analyzed for sodium and creatinine concentrations. Total amounts of sodium and creatinine excreted over the 24 hr were calculated and results expressed as ratio of sodium:creatinine.
Time frame: Immediately before the 1st dose of placebo or carbidopa to immediately before the 5th dose (approximately 24 hours)
Population: No data analysis for the following:~Healthy Placebo Group:~* 1 subject with discarded urine sample~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)~POTS Placebo Group:~* 1 subject with discarded urine sample~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | 24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine | 140 Milliequivalents per gram (mEq/g) | Standard Deviation 29 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | 24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine | 132 Milliequivalents per gram (mEq/g) | Standard Deviation 38 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | 24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine | 137 Milliequivalents per gram (mEq/g) | Standard Deviation 30 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | 24 Hour Urinary Sodium Excretion During Treatment Normalized to Creatinine | 154 Milliequivalents per gram (mEq/g) | Standard Deviation 31 |
Secondary
24 Hour Urinary Catecholamine (DOPA) Excretion During Treatment Normalized to Creatinine
Urine was collected over 24 hours during treatment. The urinary volume was measured and the urine was analyzed for creatinine and catecholamines. Total amounts of creatinine and catecholamines were calculated and the results are expressed as catecholamine:creatinine.
Time frame: Immediately before the 1st dose of Placebo or Carbidopa and ending immediately before the last dose (approximately 24 hours)
Population: No data analysis for the following participants:~Healthy Placebo:~* 1 w/ discarded urine sample~* 1 w/ urine not analyzed for catecholamines~* 1 received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa:~* 1 w/ urine not analyzed for catecholamines~* 1 received only 50mg carbidopa (wrong dose)~POTS Placebo:~* 1 w/ discarded urine sample~* 1 received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa:~* 1 received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (DOPA) Excretion During Treatment Normalized to Creatinine | 0.024 Micrograms per milligrams (ug/mg) | Standard Deviation 0.014 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (DOPA) Excretion During Treatment Normalized to Creatinine | 0.283 Micrograms per milligrams (ug/mg) | Standard Deviation 0.194 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (DOPA) Excretion During Treatment Normalized to Creatinine | 0.026 Micrograms per milligrams (ug/mg) | Standard Deviation 0.015 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (DOPA) Excretion During Treatment Normalized to Creatinine | 0.385 Micrograms per milligrams (ug/mg) | Standard Deviation 0.156 |
Secondary
24 Hour Urinary Catecholamine (Dopamine) Excretion During Treatment Normalized to Creatinine
Urine was collected over 24 hours during treatment. The urinary volume was measured and the urine was analyzed for creatinine and catecholamines. Total amounts of creatinine and catecholamines were calculated and the results are expressed as catecholamine:creatinine.
Time frame: Immediately before the 1st dose of Placebo or Carbidopa and ending immediately before the last dose (approximately 24 hours)
Population: No data analysis for the following participants:~Healthy Placebo:~* 1 w/ discarded urine sample~* 1 w/ urine not analyzed for catecholamines~* 1 received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa:~* 1 w/ urine not analyzed for catecholamines~* 1 received only 50mg carbidopa (wrong dose)~POTS Placebo:~* 1 w/ discarded urine sample~* 1 received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa:~* 1 received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (Dopamine) Excretion During Treatment Normalized to Creatinine | 0.208 Micrograms per milligrams (ug/mg) | Standard Deviation 0.061 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (Dopamine) Excretion During Treatment Normalized to Creatinine | 0.035 Micrograms per milligrams (ug/mg) | Standard Deviation 0.015 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (Dopamine) Excretion During Treatment Normalized to Creatinine | 0.24 Micrograms per milligrams (ug/mg) | Standard Deviation 0.081 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | 24 Hour Urinary Catecholamine (Dopamine) Excretion During Treatment Normalized to Creatinine | 0.038 Micrograms per milligrams (ug/mg) | Standard Deviation 0.015 |
Secondary
Plasma Catecholamines (DOPA) After the Last Dose of Placebo or Carbidopa
Blood samples were collected while resting supine for at least 30 minutes and 2 to 4 hours after lunch. For catecholamine measurements, blood was collected in chilled vacuum tubes with EDTA. Plasma was separated and stored with added reduced glutathione (Amersham International PLC) at -70°C until the assay. Plasma catecholamines were measured by a method that involves batch alumina extraction followed by high-performance liquid chromatography (HPLC) for separation with electrochemical detection and quantification.
Time frame: 8 hours after the last dose of placebo or carbidopa
Population: No data analysis for the following:~Healthy Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)~POTS Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | Plasma Catecholamines (DOPA) After the Last Dose of Placebo or Carbidopa | 1813 Picograms per milliliter (pg/mL) | Standard Deviation 463 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | Plasma Catecholamines (DOPA) After the Last Dose of Placebo or Carbidopa | 20297 Picograms per milliliter (pg/mL) | Standard Deviation 9509 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | Plasma Catecholamines (DOPA) After the Last Dose of Placebo or Carbidopa | 2104 Picograms per milliliter (pg/mL) | Standard Deviation 700 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | Plasma Catecholamines (DOPA) After the Last Dose of Placebo or Carbidopa | 25680 Picograms per milliliter (pg/mL) | Standard Deviation 13825 |
Secondary
Plasma Catecholamines (Norepinephrine) After the Last Dose of Placebo or Carbidopa
Blood samples were collected while resting supine for at least 30 minutes and 2 to 4 hours after lunch. For catecholamine measurements, blood was collected in chilled vacuum tubes with EDTA. Plasma was separated and stored with added reduced glutathione (Amersham International PLC) at -70°C until the assay. Plasma catecholamines were measured by a method that involves batch alumina extraction followed by high-performance liquid chromatography (HPLC) for separation with electrochemical detection and quantification.
Time frame: 8 hours after the last dose of placebo or carbidopa
Population: No data analysis for the following:~Healthy Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)~POTS Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | Plasma Catecholamines (Norepinephrine) After the Last Dose of Placebo or Carbidopa | 150 Picograms per milliliter (pg/mL) | Standard Deviation 46 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | Plasma Catecholamines (Norepinephrine) After the Last Dose of Placebo or Carbidopa | 181 Picograms per milliliter (pg/mL) | Standard Deviation 100 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | Plasma Catecholamines (Norepinephrine) After the Last Dose of Placebo or Carbidopa | 278 Picograms per milliliter (pg/mL) | Standard Deviation 84 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | Plasma Catecholamines (Norepinephrine) After the Last Dose of Placebo or Carbidopa | 245 Picograms per milliliter (pg/mL) | Standard Deviation 70 |
Secondary
Plasma Sodium After the Last Dose of Placebo or Carbidopa
Blood samples were collected while resting supine for at least 30 minutes and 2 to 4 hours after lunch. Samples were processed and sent to the Vanderbilt Clinical Laboratory for assay.
Time frame: 8 hours after the last dose of placebo or carbidopa
Population: No data analysis for the following:~Healthy Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)~POTS Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | Plasma Sodium After the Last Dose of Placebo or Carbidopa | 138 Milliequivalents per liter (mEq/L) | Standard Deviation 1.9 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | Plasma Sodium After the Last Dose of Placebo or Carbidopa | 138 Milliequivalents per liter (mEq/L) | Standard Deviation 1.9 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | Plasma Sodium After the Last Dose of Placebo or Carbidopa | 139 Milliequivalents per liter (mEq/L) | Standard Deviation 2.2 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | Plasma Sodium After the Last Dose of Placebo or Carbidopa | 138 Milliequivalents per liter (mEq/L) | Standard Deviation 2 |
Secondary
Supine Plasma Renin Activity 2 Hours After the Last Dose of Placebo or Carbidopa
Blood samples were collected while resting supine for at least 30 minutes and 1 1/2 to 2 hours after breakfast. Samples were processed and sent to the Vanderbilt Clinic Laboratory for assay.
Time frame: 2 hours after the last dose of placebo or carbidopa
Population: No data analysis for the following:~Healthy Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)~POTS Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | Supine Plasma Renin Activity 2 Hours After the Last Dose of Placebo or Carbidopa | 1.153 Nanograms per milliliter per hour (ng/mL | Standard Deviation 0.926 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | Supine Plasma Renin Activity 2 Hours After the Last Dose of Placebo or Carbidopa | 1.033 Nanograms per milliliter per hour (ng/mL | Standard Deviation 0.529 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | Supine Plasma Renin Activity 2 Hours After the Last Dose of Placebo or Carbidopa | 1.544 Nanograms per milliliter per hour (ng/mL | Standard Deviation 1.02 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | Supine Plasma Renin Activity 2 Hours After the Last Dose of Placebo or Carbidopa | 1.878 Nanograms per milliliter per hour (ng/mL | Standard Deviation 1 |
Secondary
Systolic Blood Pressure Measured at 8 Hours After the Last Dose of Placebo or Carbidopa
Systolic blood pressure was measured once using a Dinamap non-invasive oscillometric blood pressure monitor, 2-4 hours after lunch and after at least 30 minutes of resting supine.
Time frame: 8 hours after the last dose of placebo or carbidopa
Population: No data analysis for the following:~Healthy Placebo Group:~* 1 subject with missing systolic blood pressure 8-hours after the last dose of Placebo~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~Healthy Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)~POTS Placebo Group:~* 1 subject who received only 50mg carbidopa (data for all arms excluded)~POTS Carbidopa Group:~* 1 subject who received only 50mg carbidopa (wrong dose)
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Healthy Participants Who Received Placebo as Treatment A or Treatment B | Systolic Blood Pressure Measured at 8 Hours After the Last Dose of Placebo or Carbidopa | 103 millimeters of mercury (mmHg) | Standard Deviation 4 |
| Healthy Participants Who Received Carbidopa as Treatment A or Treatment B | Systolic Blood Pressure Measured at 8 Hours After the Last Dose of Placebo or Carbidopa | 101 millimeters of mercury (mmHg) | Standard Deviation 8 |
| Postural Tachycardia Syndrome (POTS) Participants Who Received Placebo as Treatment A or Treatment B | Systolic Blood Pressure Measured at 8 Hours After the Last Dose of Placebo or Carbidopa | 102 millimeters of mercury (mmHg) | Standard Deviation 9 |
| Postural Tachycardia Syndrome (POTS) Patients Who Received Carbidopa as Treatment A or Treatment B | Systolic Blood Pressure Measured at 8 Hours After the Last Dose of Placebo or Carbidopa | 101 millimeters of mercury (mmHg) | Standard Deviation 10 |