ACC

Pharmacotherapeutic group: Expectorants, excluding combinations with cough suppressants, mucolytics ATC code: R05CB01 Mechanism of action and pharmacodynamic effects Acetylcysteine depolymerises mucus in vitro by breaking the disulphide bonds between macromolecules present in the mucus, thereby reducing mucosal viscosity. Acetylcysteine activates the ciliated epithelium.‍​‍‍‍​‍‍‍‍‍‍‍‍​‍ Thus, the fluidity and passage of bronchial secretions is improved, which facilitates expectoration and improves mucociliary clearance. In in vitro human respiratory tract model systems, acetylcysteine has been shown to inhibit the adherence of bacteria to ciliated epithelial cells. Acetylcysteine acts as an antioxidant and is a precursor of cysteine, the rate-limiting amino acid for glutathione synthesis in most tissues. Glutathione is present in the epithelial lining fluid of the normal lower respiratory tract, where it is thought to play a major role in providing antioxidant protection to the epithelial cells. Oxidative mechanisms are involved in the pathogenesis of a number of pulmonary diseases.