SynthesisFrontiers in physiology2026
Effect of inhaled anticholinergics on bronchial secretions: a systematic review.
Synthesis in Frontiers in physiology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
- Erratum issued
Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Background: Inhaled anticholinergics are commonly used in chronic respiratory diseases with the intention of reducing bronchial secretions in addition to their bronchodilatory effects. However, evidence regarding their direct influence on mucus production and clearance remains limited and fragmented. This study aimed to identify, evaluate, and synthesize the available evidence on the effects of inhaled and nebulized anticholinergics on mucus volume, rheological properties, mucociliary clearance, cough, and pulmonary function in adults. Methods: A systematic review was conducted following PRISMA 2020 guidelines and registered in PROSPERO (CRD42024575999). Comprehensive searches were performed in PubMed, OVID, Embase, SciELO, EBSCO, ScienceDirect, and Cochrane Library without date restrictions. Randomized and non-randomized studies assessing inhaled or nebulized anticholinergics were included. Risk of bias was evaluated using the RoB 2 and ROBINS-I tools. Results: Out of 2,449 records identified, eight studies comprising 403 participants met the inclusion criteria. Under stable clinical conditions, inhaled ipratropium and tiotropium showed no significant changes in sputum volume, viscosity, or mucociliary clearance compared with placebo. In acute or procedural settings, such as bronchoscopy, nebulized ipratropium was associated with a reduction in bronchial secretion grade and cough frequency. Tiotropium treatment demonstrated decreases in sputum solid fraction and mucin content (MUC5AC and MUC5B). None of the included studies reported impairment of mucociliary clearance or serious adverse events related to treatment. Conclusion: Current evidence does not demonstrate a consistent effect of inhaled or nebulized anticholinergics on sustained reduction of bronchial secretions. However, their use does not appear to cause adverse changes in mucus production or clearance and may induce transient effects during acute cholinergic stimulation. Overall, the findings support a favorable safety profile of these agents regarding airway secretion management. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42024575999.
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