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Ambroxol as a Treatment for Parkinson Disease Dementia: A Randomized Clinical Trial
Silveira CRA, Coleman KKL, Borron K, Tirona RG, Rupar CA, Zou G, Hegele RA, Wellington C et al.. JAMA neurology, 2025-06-30
Topic: Amyloid, tau and blood-test diagnosis
Results A total of 75 patients were screened, and 55 were randomized. Mean (SD) β-glucocerebrosidase levels were higher at week 26 (ambroxol, 12.45 [1.97] nmol/h/mg; 91% CI, 11.54-13.36 nmol/h/mg); placebo, 8.50 [1.96] nmol/h/mg; 91% CI, 7.65-9.34 nmol/h/mg; P = .05) in the ambroxol group compared with placebo. Conclusions and relevance Results of this randomized clinical trial reveal that ambroxol was safe, well-tolerated, and demonstrated target engagement.
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APA 7th
Silveira, C. R. A., Coleman, K. K. L., Borron, K., Tirona, R. G., Rupar, C. A., Zou, G., et al. (2025). Ambroxol as a Treatment for Parkinson Disease Dementia: A Randomized Clinical Trial. JAMA neurology. https://doi.org/10.1001/jamaneurol.2025.1687
Vancouver
Silveira CRA, Coleman KKL, Borron K, Tirona RG, Rupar CA, Zou G, et al. Ambroxol as a Treatment for Parkinson Disease Dementia: A Randomized Clinical Trial. JAMA neurology. 2025. doi:10.1001/jamaneurol.2025.1687. PMID: 40587145.
BibTeX
@article{silveira2025-40587145,
author = {Silveira, C. R. A. and Coleman, K. K. L. and Borron, K. and Tirona, R. G. and Rupar, C. A. and Zou, G. and Hegele, R. A. and Wellington, C. and others},
title = {{Ambroxol as a Treatment for Parkinson Disease Dementia: A Randomized Clinical Trial}},
journal = {JAMA neurology},
year = {2025},
doi = {10.1001/jamaneurol.2025.1687},
pmid = {40587145},
url = {https://doi.org/10.1001/jamaneurol.2025.1687}
}
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
Key findings
- Results A total of 75 patients were screened, and 55 were randomized.
- Mean (SD) β-glucocerebrosidase levels were higher at week 26 (ambroxol, 12.45 [1.97] nmol/h/mg; 91% CI, 11.54-13.36 nmol/h/mg); placebo, 8.50 [1.96] nmol/h/mg; 91% CI, 7.65-9.34 nmol/h/mg; P = .05) in the ambroxol group compared with placebo.
- Conclusions and relevance Results of this randomized clinical trial reveal that ambroxol was safe, well-tolerated, and demonstrated target engagement.
Why it matters
In this randomized trial of 55 patients with Parkinson disease dementia, ambroxol was safe, well-tolerated, and raised β-glucocerebrosidase levels compared with placebo. The study only showed this target engagement, not any effect on thinking or on Alzheimer's disease.
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Study details
- Study designclinical trial
- Participants75
- Effect size86.4%; 79.2%
- Evidence strengthHigh
How this study scored 58/100
Published in a leading specialty journal. Scored zero for study design because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (JAMA neurology) |
| Journal's citation record | 2 / 4 | JAMA Neurology: journal h-index 235 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | Design recorded as “clinical trial”, which our rubric does not rank (not stated in the record — scored 0) |
| Strength of evidence | 5 / 5 | Rated “high” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 4 / 5 | 2025 — within 3 year(s) of the newest study here |
| Sample size | 1 / 4 | 75 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 1 / 2 | Randomised (as stated in the record) |
| Times cited | 3 / 7 | Cited 24 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 8.0 citations a year over 3 year(s) since 2025 |
| Impact for its field and year | 4 / 6 | Cited 13.5× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 2 / 4 | Cited 24 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author Stephen Pasternak: h-index 48 (OpenAlex, whole career) |
| Institution's track record | 2 / 3 | University of Toronto: institution h-index 1,923 (OpenAlex) |
| Multi-centre collaboration | 3 / 3 | OpenAlex lists 16 institution(s) in 1 country |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 40587145) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 58 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
- DOI: 10.1001/jamaneurol.2025.1687
- PubMed: 40587145
- Original source →
- Free full text: PubMed Central →
Full text: free to read — PubMed Central lists this copy as free to read: the link above (checked 10 Oct 2026).
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