Adjusting the carbidopa/levodopa ratio to reduce orthostatic hypotension in MSA-P and Parkinson's
A Monocentric, Randomized, Double-blind Study to Assess the Feasibility of Conducting a Full-scale Randomized Controlled Trial (RCT) Assessing the Effect of Carbidopa/Levodopa Ratio on Orthostatic Hypotension (OH) in Multiple System Atrophy - Parkinsonian Type (MSA-P) and Parkinson Disease (PD) Patients (CARBIDOH)
This trial will test whether changing the carbidopa-to-levodopa ratio can reduce standing-related low blood pressure and symptoms in people with Parkinson disease or parkinsonian-type multiple system atrophy who are taking dopaminergic medication.
Quick facts
| Phase | Phase1; Phase2 |
|---|---|
| Study type | Interventional |
| Enrollment | 36 (estimated) |
| Sex | All |
| Sponsor | University of Lausanne Hospitals Academic / other |
| Locations | 2 sites (Lausanne, Canton of Vaud and 1 other locations) |
| Trial ID | NCT06831500 on ClinicalTrials.gov |
What this trial studies
This Phase 1/2 interventional feasibility study enrolls adults with MSA-P or Parkinson disease who have orthostatic hypotension and are on levodopa combined with carbidopa or benserazide. Participants will undergo controlled administration of carbidopa/levodopa with adjustments to the carbidopa-to-levodopa ratio while investigators monitor standing and supine blood pressure and symptom scores. Study visits include a required medication withdrawal period before testing, orthostatic vital sign measurements, and symptom assessments using established autonomic questionnaires. The single-center trial at CHUV (Lausanne) aims to collect safety and preliminary efficacy data to inform larger trials.
Who should consider this trial
Good fit: Adults aged 18–79 with clinically diagnosed MSA-P or Parkinson disease who experience orthostatic hypotension, are currently taking levodopa combined with carbidopa or benserazide, and can safely undergo the required medication withdrawal are ideal candidates.
Not a fit: Patients with severe congestive heart failure (NYHA III–IV), major cognitive impairment/dementia, those not on levodopa-based therapy, or who cannot tolerate medication withdrawal are unlikely to benefit or be eligible.
Why it matters
Potential benefit: If successful, adjusting the carbidopa/levodopa ratio could reduce drops in blood pressure when standing and lessen dizziness or fainting, improving daily safety and function.
How similar studies have performed: Previous research has documented that dopaminergic medications can worsen orthostatic hypotension, but controlled trials specifically altering the carbidopa/levodopa ratio are limited, so this approach is relatively novel and exploratory.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: 1. Informed consent form signed. 2. Patient over 18 years and under 80 years of age. 3. Patient with Multiple System Atrophy- Parkinsonian type (MSA-P) (confirmed by diagnostic criteria for clinically established and clinically probable multiple system atrophy (11); OR Patient with Parkinson Disease (PD) (12) presenting OH symptoms (getting at least one point at the 3 questions - n° 14, 15 and 16 - of the SCOPA-AUT scale that address orthostatic hypotension symptoms). 4. Patient currently receiving Dopamine-Replacement Therapy (i.e. Levodopa combined with Carbidopa or Benserazide). Exclusion Criteria: 1. Patient unable to stand an overnight (at least 12 hours) withdrawal of their immediate-release DRT (last extended-, delayed-, or controlled-release dosage must be taken minimum 24 hours prior to the test). 2. Patient with known congestive heart failure, grades C and D, NYHA III and IV. 3. Patient with dementia (i.e. major cognitive impairment) associated to MSA-P or PD, 4. Patient with mild cognitive impairment, and unable to provide or understand informed consent, i.e. who does not have full capacity for discernment. 5. Current participation to other clinical trials. 6. Pregnant or lactating woman or willing to become pregnant.
Where this trial is running
Lausanne, Canton of Vaud and 1 other locations
- Centre Hospitalier Universitaire Vaudois (CHUV) — Lausanne, Canton of Vaud, Switzerland (Recruiting)
- Centre Hospitalier Universitaire Vaudois — Lausanne, Canton of Vaud, Switzerland (Recruiting)
Study contacts
- Study coordinator: Julien BALLY, Dr PD-MER
- Email: julien.bally@chuv.ch
- Phone: +41 79 556 78 19
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.