Inhaled alkaline hypertonic divalent salts reduce refractory chronic cough frequency
Summary
This is an exploratory, single-blind, nasal saline-controlled study involving 12 patients with refractory chronic cough, designed to examine the cough suppression efficacy of alkaline salts, monitored objectively with the previous version of the Hyfe CoughMonitor Suite.
Background Treatment of chronic cough remains a challenge. It was hypothesised that inhaled alkaline hypertonic divalent salts (alkaline HDS) might provide relief for refractory chronic cough by laryngeal and tracheal hydration.
Methods We conducted an exploratory, single-blinded, nasal saline-controlled study in 12 refractory chronic cough patients to examine cough suppression efficacy of an alkaline HDS composition (SC001) at pH 8 or pH 9 administered by nasal inhalation. As control, we used nasal saline with the same hand-held pump spray aerosol device. Each subject was monitored continuously using a Hyfe CoughMonitor Suite's watch (older version than available in 2024) for 1 week of baseline, 1 week of control treatment and 1 week of active treatment.
Results Baseline daily cough rates ranged from 4 to 34 coughs·h−1 with mean visual analogue score 65±17 pre- and post-baseline testing. Control-adjusted efficacy of cough rate reduction ranged from 15% (p=0.015) (from Day 1) to 23% (p=0.002) (from Day 3). Control-adjusted efficacy was highest with SC001 pH 9 (n=5), ranging from 25% (p=0.03) (from Day 1) to 35% (p=0.02) (from Day 3), and lowest for SC001 pH 8 (n=7), ranging from 9% (p=0.08) (from Day 1) to 16% (p=0.02) (from Day 3). Hourly cough counts and visual analogue score correlated for baseline (r=0.254, p=0.02) and control (r=0.299, p=0.007) monitoring weeks. Treatment improved this correlation (r=0.434, p=0.00006). No adverse events were reported.
Conclusions Alkaline (pH 9) HDS aerosol is a promising treatment for refractory chronic cough and should be further evaluated.
