N-acetylcysteine is an established mucolytic and anti-oxidant medicine for acute and chronic respiratory conditions1. In severely ill patients, intravenous administration of this agent may be the preferred route. However, no large-scale trials have studied the efficacy of intravenous N-acetylcysteine as a mucolytic and expectorant therapy.
To address this gap in the literature, Prof. Alberto Papi (University of Ferrara, Italy) and co-investigators randomised 333 patients with acute respiratory conditions and abnormal mucus secretion 1:1:1 to standard of care plus a 7-day course of intravenous N-acetylcysteine (600mg, twice daily), standard of care plus intravenous ambroxol hydrochloride (30mg, twice daily), or standard of care plus placebo. Prof. Papi presented the results of the primary endpoints, which were the change from baseline to day 7 in mean sputum viscosity score and expectoration difficulty score, comparing the N-acetylcysteine arm to the placebo arm2. The primary endpoints were measured at 4-point ordinal scales.
The sputum viscosity score had improved significantly more in the N-acetylcysteine arm than in the placebo arm (-1.2 vs -1.0; P<0.001). Similarly, the expectoration difficulty score had dropped with 1.4 points in the N-acetylcysteine arm and with 1.1 points in the placebo arm, significantly favouring the experimental arm (P=0.002). Prof. Papi added that the observed safety profile is in line with the good tolerability of intravenous N-acetylcysteine (600mg, twice daily) that had been reported in previous smaller studies.
“This is the first large, randomised-controlled trial to demonstrate clinical benefits of intravenous N-acetylcysteine in patients with respiratory diseases and abnormal mucus secretion,” decided Prof. Papi.