Early but transient symptomatic benefit of intranasal Bencycloquidium bromide in adults with the common cold

The phase 3 randomised trial by He et al. demonstrated that intranasal bencycloquidium bromide significantly reduced rhinorrhoea and nasal congestion compared with placebo in adults with the common cold.1 Examination of the daily symptom trajectories indicates that the between-group difference was greatest within the first 48–72 h and diminished thereafter, with no meaningful separation by day 5. This temporal pattern suggests that bencycloquidium bromide accelerates early symptom resolution rather than altering the overall duration of illness, consistent with the self-limiting nature of viral upper respiratory infections.2 An underappreciated observation is that improvement in nasal congestion was at least comparable to that for rhinorrhoea. This finding implies that muscarinic antagonism may influence nasal vascular tone in addition to reducing glandular secretion, a mechanism supported by experimental data on airway muscarinic receptor pathways.3 Such dual activity may distinguish bencycloquidium bromide from earlier intranasal anticholinergics that primarily target rhinorrhoea. Certain methodological issues warrant careful consideration. The placebo contained isotonic saline, which itself alleviates nasal symptoms and likely attenuated the apparent incremental benefit of active treatment.4 The study population was predominantly young, healthy Han Chinese adults,1 limiting generalisability to older or more diverse groups, and viral confirmation was not performed.5