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A Study of Pyridostigmine in Postural Tachycardia Syndrome

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT00409435
Recruitment Status : Recruiting
First Posted : December 8, 2006
Last Update Posted : March 7, 2022
National Institutes of Health (NIH)
Information provided by (Responsible Party):
Phillip Low, Mayo Clinic

Brief Summary:
This is a 3-day study comparing pyridostigmine versus placebo in the treatment of postural tachycardia syndrome (POTS). The researchers expect pyridostigmine to improve tachycardia and stabilize blood pressure.

Condition or disease Intervention/treatment Phase
Postural Tachycardia Syndrome Drug: pyridostigmine Drug: Placebo Not Applicable

Detailed Description:

The study will be done at the outpatient General Clinical Research Center (GCRC) at Charlton 7 and will involve two visits. Visit 1 will take about 3 hours, and Visit 2 will occur 2 days after Visit 1 and will take about 2 hours.

You will be put in one of two groups by chance (as in the flip of a coin). One group will be taking placebo (an inactive substance), the other group 180 mg pyridostigmine in time release formulation. Both placebo and pyridostigmine will look identical and will be taken as one capsule per day for 3 days. Neither you nor the study doctor will know at the time of treatment whether the treatment being given is active or inactive. However, in case of an emergency, this information will be available.

For each of the two visits, the following tests and procedures will be performed:

  • When you arrive at the GCRC, you will have a general medical and neurological examination and height and weight measurement.
  • Questionnaires. You will be asked to answer a series of questions on your autonomic symptoms (such as rapid heart rate, feeling of tiredness, cold and sweaty hands) at each of your two visits. The questionnaire you will be given during your first visit should take approximately 30 minutes to complete. The questionnaire you will be given during your second visit should take approximately 10 minutes to complete.
  • Autonomic Reflex Screen. An autonomic reflex screen will be done during each visit. This consists of the following:

    • Quantitative sudomotor axon reflex test (QSART): QSART is a routine clinical test that evaluates the response of the sweat gland to a drug, acetylcholine. One capsule is placed on your forearm and three on your leg and foot. The testing is done by passing a small electrical current, for 5 minutes, to activate the nerves that supply the sweat glands. You will feel a slight burning sensation.
    • Cardiovascular recordings: Blood pressure, heart rate, and other cardiovascular measurements will be studied by placing electrodes on the chest and a finger or wrist cuff for continuous blood pressure recordings.
    • Valsalva maneuver: This involves blowing very hard into a bugle (like blowing up a balloon) for 15 seconds.
    • Head-up tilt: Following a period of rest (at least 5 minutes), you will be tilted up to an angle of not more than 80 degrees and recordings will be made for up to 30 minutes. On Visit 1, one hour after you have taken the study medication, this test will be repeated. This test will be done only once on Visit 2.
    • Hormone level measurements: This will be done during each visit. An IV will be inserted into a vein in your arm from which approximately one teaspoon of blood will be drawn while you are lying down and one teaspoon after standing up. This will be repeated only on Visit 1, one hour after the study drug is given. A total of four teaspoons of blood will be drawn on Visit 1 and 2 teaspoons will be drawn on Visit 2.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 50 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Double-Blind, Placebo-Controlled Study of Pyridostigmine in Postural Tachycardia Syndrome
Study Start Date : October 2006
Estimated Primary Completion Date : February 2023
Estimated Study Completion Date : February 2023

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Active Comparator: pyridostigmine
Active study drug
Drug: pyridostigmine
one 180 mg capsule per day for 3 days

Placebo Comparator: Placebo
Drug: Placebo
one capsule per day for 3 days

Primary Outcome Measures :
  1. Change in orthostatic symptoms using Composite Autonomic Symptom Scale (COMPASS) change [ Time Frame: 3 days ]

Secondary Outcome Measures :
  1. Heart rate response to head-up tilt [ Time Frame: 3 days ]
  2. Plasma norepinephrine change [ Time Frame: 3 days ]

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   15 Years to 55 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

Diagnosis of postural tachycardia syndrome using the following criteria:

  • Orthostatic heart rate increment greater than or equal to 30 beats per minute (bpm) within 5 minutes of head-up tilt.
  • Symptoms of orthostatic intolerance. These include weakness, lightheadedness, blurred vision, nausea, palpitations, and difficulty with concentration and thinking.

Both criteria must be fulfilled.

Exclusion Criteria:

  • Pregnant or lactating women
  • Presence of failure of other organ systems or systemic illness that could affect autonomic function or the patient's ability to cooperate with the study
  • Hypothyroidism or hyperthyroidism
  • Clinically significant coronary artery disease
  • Medications that could interfere with autonomic testing
  • Previous treatment with pyridostigmine for POTS. Patients must not have taken pyridostigmine in the past month

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00409435

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United States, Minnesota
Mayo Clinic Recruiting
Rochester, Minnesota, United States, 55905
Contact: Toni Gehrking    507-284-0336   
Principal Investigator: Phillip A. Low, M.D.         
Sponsors and Collaborators
Mayo Clinic
National Institutes of Health (NIH)
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Principal Investigator: Phillip A. Low, M.D. Mayo Clinic
Additional Information:
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Responsible Party: Phillip Low, MD, Mayo Clinic Identifier: NCT00409435    
Other Study ID Numbers: 06-002442
First Posted: December 8, 2006    Key Record Dates
Last Update Posted: March 7, 2022
Last Verified: March 2022
Keywords provided by Phillip Low, Mayo Clinic:
Postural tachycardia syndrome (POTS)
Additional relevant MeSH terms:
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Postural Orthostatic Tachycardia Syndrome
Pathologic Processes
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Cardiac Conduction System Disease
Orthostatic Intolerance
Primary Dysautonomias
Autonomic Nervous System Diseases
Nervous System Diseases
Pyridostigmine Bromide
Cholinesterase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Cholinergic Agents
Neurotransmitter Agents
Physiological Effects of Drugs