Parkinson DiseasePhase 2NCT05603715
Pyridostigmine for the Treatment of Constipation in Parkinson Disease
A Phase 2 study testing Pyridostigmine Bromide in people with Parkinson Disease and Constipation, run by University of Vermont Medical Center at 1 site in United States.
Trial summary
Constipation is a common and debilitating non-motor symptom of Parkinson disease (PD) that often precedes the onset of classic motor symptoms by decades. There is no standardized algorithm for managing constipation in this patient population, nor are there dedicated treatments. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Parkinson Disease, Constipation
- What is being tested?
- Pyridostigmine Bromide
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 16 participants
- Where
- 1 siteUnited States
- Study dates
- 10 Aug 2022to 31 Dec 2026
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥ 18 years
- Be able to provide signed informed consent
- Stated ability and willingness to comply with all study procedures
- Able to take oral medications
- Females of reproductive potential who are sexually active must be willing to use two of the following highly effective methods of contraception for the duration of study participation and for an additional 28 days after the end of study drug administration: barrier contraception (female condom, diaphragm, cervical cap with/without spermicide), hormonal contraception, or intrauterine device; OR one of the previously mentioned methods AND partner must use barrier contraception (male condom with/without spermicide)
- Males of reproductive potential who are sexually active must be willing to use the following highly effective methods of contraception for the duration of study participation and for an additional 28 days after the end of study drug administration: barrier contraception (male condom with/without spermicide) AND partner must be postmenopausal, use hormonal contraception, have an intrauterine device, or use barrier contraception (female condom, diaphragm, cervical cap with/without spermicide)
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- Meet United Kingdom Parkinson's Disease Society Brain Bank Criteria:
- Diagnosis of a parkinsonism:
- Bradykinesia, plus at least one of the following:
- Muscular rigidity
- 4-6 Hz resting tremor
- Postural stability not caused by primary visual, vestibular, cerebellar or proprioceptive dysfunction
- At least three supportive criteria:
- Unilateral onset of symptoms
- Rest tremor
- Progressive symptoms
- Persistent asymmetry affecting the side of onset most
- Excellent response to levodopa
- Severe levodopa-induced chorea
- Levodopa response for five years or more
- Clinical course of 10 years or more
- Fulfill the ROME IV Criteria for Functional Constipation, with a specific requirement that the patient must have three or fewer defecations per week (criterion Ai):
- Must include two or more of the following:
- Three or fewer defecations per week ii. Straining during > 25% of defecations iii. Lumpy or hard stools in > 25% of defecations iv. Sensation of incomplete evacuation for > 25% of defecations v. Sensation of anorectal obstruction/blockage for > 25% of defecations vi. Manual maneuvers to facilitate > 25% of defecations
- Loose stools are rarely present without the use of laxatives
- Insufficient criteria for irritable bowel syndrome
- Criteria 1-3 must be fulfilled for at least three months with onset of symptoms at least six months prior to diagnosis
Who cannot join
- Diagnosis of atypical parkinsonism
- Diagnosis of drug-induced parkinsonism
- Diagnosis of vascular parkinsonism
- Known allergy to pyridostigmine bromide or other study drug components
- Current or recent (within 90 days of enrollment) use of pyridostigmine for any reason
- History of any bowel surgery
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- History of bladder or bowel obstruction
- Severe asthma or chronic obstructive pulmonary disease
- Meet exclusion criteria noted in the UK Parkinson's Disease Society Brain Bank Criteria, at the PI's discretion:
- A.Exclusion of any of the following:
- Repeated strokes with stepwise progression of parkinsonian features
- Repeated head injury
- Definite encephalitis
- Oculogyric crises
- Neuroleptic treatment at onset of symptoms
- Greater than one affected relative
- Sustained remission
- Strictly unilateral features after 3 years
- Supranuclear gaze palsy
- Cerebellar signs
- Early severe autonomic involvement
- Early severe dementia
- Babinski sign
- Cerebral tumor or communicating hydrocephalus
- Negative response to large doses of levodopa
- 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine exposure
- Significant abnormalities on laboratory analysis (complete blood count, comprehensive metabolic panel, thyroid stimulating hormone) conducted at the screening visit or within the three months prior if available for review
- Significant abnormalities on screening electrocardiogram conducted at the screening visit or within the three months prior if available for review
- Positive pregnancy test (if female of child-bearing age)
- Antibiotic use within two weeks prior to enrollment
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
University of Vermont Medical Center
Burlington, Vermont, 05401
Kaysi Herrera Pujols, 802-847-4589, Kaysi.HerreraPujols@uvmhealth.org
Lisa Deuel, MD
About this study
Constipation is a common and debilitating non-motor symptom of Parkinson disease (PD) that often precedes the onset of classic motor symptoms by decades. There is no standardized algorithm for managing constipation in this patient population, nor are there dedicated treatments. Studies suggest that constipation can affect quality of life to a significant degree, in many cases just as much as motor symptoms. There is an unmet need for effective treatment options for constipation in this patient population. The goal of this study is to determine the efficacy and safety of pyridostigmine as a treatment for chronic constipation in patients with PD.
Read the detailed description
This is a 13-15 week open-label, dose escalation trial of pyridostigmine 60-180mg three times a day (TID) for the treatment of constipation in patients with Parkinson disease.
- Conditions
- Parkinson Disease, Constipation
- Being tested
- Pyridostigmine Bromide
- Medical subject headings
- Parkinson Disease, Constipation
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Pyridostigmine BromideDrug
Dose escalation trial of Pyridostigmine bromide oral tablets 60-180 mg TID for four weeks
| Study group | Role | What they receive |
|---|---|---|
| Pyridostigmine Bromide | Other | Open Label Receives: Drug: Pyridostigmine Bromide |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in number of spontaneous bowel movements per week after the study intervention
Participants will keep a Bowel Movement Journal during the four week Screening Phase, from which the pre-intervention average number of spontaneous bowel movements will be calculated. They will again keep a Bowel Movement Journal for the four weeks of the Treatment Phase, from which the postintervention average number of spontaneous bowel movements will be calculated.
Measured: 13-15 Weeks
Secondary outcomes (7)
Changes from Baseline to the End of Study Visit in the Gastrointestinal Dysfunction Scale in Parkinson's Disease (GIDS-PD)
The Gastrointestinal Dysfunction Scale in Parkinson's Disease (GIDS-PD) is a PD-specific self-administered scale that evaluates various gastrointestinal symptoms including, but not limited to, constipation, and lifestyle factors that impact symptoms such as diet and physical activity. The GIDS-PD score is broken down into 3 subscores: constipation, bowel irritability, and upper GI. There are 12 items, and each item score is calculated by multiplying the frequency score and the severity score. The total score is calculated by adding the scores of items 1-12. The minimum score is 1 and the maximum score is 108.
While the GIDS-PD is typically completed based on symptoms over the past six months, the investigator will ask the participant to consider their symptoms over the past one month.
Measured: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the Cleveland Clinic Constipation Scoring System (CCCSS)
The Cleveland Clinic Constipation Scoring System (CCCSS) is a 0-30 point self-administered scale comprised of eight variables (i.e., frequency, difficulty, completeness, pain, time, assistance, failure and history) quantifying the degree of constipation. A score of 0 is normal while a score of 30 indicates severe constipation.
While the CCCSS is typically completed based on symptoms over the past six months, the investigator will ask the participants to consider their symptoms over the past one month.
Measured: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the MDS-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Parts I-IV
The MDS sponsored revision of the Unified Parkinson's Disease Rating Sale (MDS-UPDRS) was developed to evaluate various aspects of Parkinson's disease including non-motor and motor experiences of daily living and motor complications. It includes a motor evaluation and characterizes the extent and burden of disease across various populations. The MDS-UPDRS is broken down into 4 parts: Part I (non-motor experiences of daily living), Part II (motor experiences of daily living), Part III (motor examination), and Part IV (motor complications).
Measured: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the International Parkinson and Movement Disorder Society Non-Motor Rating Scale (MDS-NMS)
The International Parkinson and Movement Disorder Society Non-Motor Rating Scale (MDS-NMS) is a revision of the Non-Motor Symptoms Scale (NMSS) and was developed to improve and refine the assessment of non-motor symptoms in Parkinson's disease (PD). This rater completed assessment measures frequency and severity of 13 non-motor domains, over 52 items and covers a range of key non-motor symptoms both PD and treatment related, and in greater depth, compared with the NMSS. The scale also has a new MDS-NMS Non-Motor Fluctuations (NMF) Subscale to assess changes in non-motor symptoms in relation to the timing of antiparkinsonian medications across 8 domains. The MDS-NMS is a valid and reliable rating scale that measures the burden of non-motor symptoms, including non-motor fluctuations, in PD patients.
Measured: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the Parkinson's Disease Questionnaire (PDQ-39).
The Parkinson's Disease Questionnaire (PDQ-39) is a self-administered survey assessing difficulties across eight dimensions of health, specifically, mobility, activities of daily living, emotional wellbeing, stigma, social support, cognition, communications and bodily discomfort. Each of 39 items are scored on a scale of 0-4, with higher scores indicating more profound difficulties. The PDQ-39 is completed based on symptoms over the past one month.
Measured: 9-11 Weeks
Changes from Baseline to the End of Study Visit in Beck Depression Inventory-II (BDI-II)
The Beck Depression Inventory-II (BDI-II) is a self-administered survey assessing the presence and severity of depression. Each of 21 items are scored from 0-3, with higher scores indicating more severe depressive symptoms. The BDI-II is completed based on symptoms over the past two weeks.
Measured: 9-11 Weeks
Number of adverse events and serious adverse events that occur during the trial
The investigator will monitor for any potential study drug related adverse events. The pyridostigmine bromide package insert does not recommend any routine safety assessments.
Measured: 13-15 Weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Nov 2022
- Study start10 Aug 2022
- Primary completion31 Dec 2026 (estimated)
- Study completion31 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Parkinson DiseaseStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 16 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Vermont Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Lisa Deuel, MD, University of Vermont Medical Center
- Investigators
- Lisa M Deuel, MD, Principal investigator, University of Vermont
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05603715
- Sponsor's protocol ID
- STUDY00001877
- Status last verified
- Feb 2026
- First submitted
- 12 Sep 2022
- Last updated
- 23 Feb 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Pyridostigmine for the Treatment of Constipation in Parkinson Disease
- ClinicalTrials.gov ID
- NCT05603715
- Acronym / sponsor ID
- STUDY00001877
- Conditions
- Parkinson Disease, Constipation
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 16 participants (estimated)
- Lead sponsor
- University of Vermont Medical CenterUniversity, hospital or other
- Study start
- 10 Aug 2022 (actual)
- Primary completion
- 31 Dec 2026 (estimated)
- Study completion
- 31 Dec 2026 (estimated)
- First posted
- 3 Nov 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Constipation is a common and debilitating non-motor symptom of Parkinson disease (PD) that often precedes the onset of classic motor symptoms by decades. There is no standardized algorithm for managing constipation in this patient population, nor are there dedicated treatments. Studies suggest that constipation can affect quality of life to a significant degree, in many cases just as much as motor symptoms. There is an unmet need for effective treatment options for constipation in this patient population. The goal of this study is to determine the efficacy and safety of pyridostigmine as a treatment for chronic constipation in patients with PD.
Detailed description
This is a 13-15 week open-label, dose escalation trial of pyridostigmine 60-180mg three times a day (TID) for the treatment of constipation in patients with Parkinson disease.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Pyridostigmine Bromide | Other | Drug: Pyridostigmine BromideOpen Label |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (27 listed)
- Age ≥ 18 years
- Be able to provide signed informed consent
- Stated ability and willingness to comply with all study procedures
- Able to take oral medications
- Females of reproductive potential who are sexually active must be willing to use two of the following highly effective methods of contraception for the duration of study participation and for an additional 28 days after the end of study drug administration: barrier contraception (female condom, diaphragm, cervical cap with/without spermicide), hormonal contraception, or intrauterine device; OR one of the previously mentioned methods AND partner must use barrier contraception (male condom with/without spermicide)
Key exclusion criteria (30 listed)
- Diagnosis of atypical parkinsonism
- Diagnosis of drug-induced parkinsonism
- Diagnosis of vascular parkinsonism
- Known allergy to pyridostigmine bromide or other study drug components
- Current or recent (within 90 days of enrollment) use of pyridostigmine for any reason
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Pyridostigmine BromideDose escalation trial of Pyridostigmine bromide oral tablets 60-180 mg TID for four weeks | Drug | Pyridostigmine Bromide |
Primary outcome
Change in number of spontaneous bowel movements per week after the study intervention
Time frame: 13-15 Weeks
Participants will keep a Bowel Movement Journal during the four week Screening Phase, from which the pre-intervention average number of spontaneous bowel movements will be calculated. They will again keep a Bowel Movement Journal for the four weeks of the Treatment Phase, from which the postintervention average number of spontaneous bowel movements will be calculated.
7 secondary outcomes
Changes from Baseline to the End of Study Visit in the Gastrointestinal Dysfunction Scale in Parkinson's Disease (GIDS-PD)
Time frame: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the Cleveland Clinic Constipation Scoring System (CCCSS)
Time frame: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the MDS-Sponsored Revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Parts I-IV
Time frame: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the International Parkinson and Movement Disorder Society Non-Motor Rating Scale (MDS-NMS)
Time frame: 9-11 Weeks
Changes from Baseline to the End of Study Visit in the Parkinson's Disease Questionnaire (PDQ-39).
Time frame: 9-11 Weeks
Changes from Baseline to the End of Study Visit in Beck Depression Inventory-II (BDI-II)
Time frame: 9-11 Weeks
Number of adverse events and serious adverse events that occur during the trial
Time frame: 13-15 Weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Feb 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Lisa M Deuel, MD principal investigator
University of Vermont
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Pyridostigmine Bromide in people with Parkinson Disease and Constipation, run by University of Vermont Medical Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 27 inclusion and 30 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 23 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Kaysi Herrera Pujols ((802) 847-4589, Kaysi.HerreraPujols@uvmhealth.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in number of spontaneous bowel movements per week after the study intervention (time frame: 13-15 Weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Feb 2026.