Mucolytic agents

Mucolytic agents

Mucus is largely composed of glycoproteins. These are large molecules containing several disulfide bridges. Mucolytic agents are sulfur compounds (acetylcysteine) such as N-acetylcysteine that break up the disulfide bridges making the molecules smaller and the mucus more viscous. They act mainly when applied directly by inhalation or during bronchoscopy. Their effectiveness when used orally is doubtful.


Completely different from sulfur compounds is DNase (not shown), which cleaves long DNA molecules. In cystic fibrosis (CF), inflammatory cells are abundant in the airway lumen and their DNA is released after degradation. The long molecules make the mucus very sticky. DNase is often very effective in CF making the sputum watery within a short time. DNase is not beneficial to all CF patients however.


DNAse and N-acetylcysteine work best when inhaled. 


Mucolytic agents decrease mucus production.


Mucolytic agents improve mucociliary clearance.