Table. 1—

Mucoactive drugs and their potential mechanisms of action

Mucoactive drugs	Potential mechanism of action
Expectorants
Hypertonic saline	Increases secretion volume and/or hydration
Guaifenesin	Stimulates secretion and reduces mucus viscosity
Mucoregulators
Carbocysteine	Metabolism of mucus producing cells, antioxidant and anti-inflammatory effects, modulates mucus production
Anticholinergic agents	Decreases secretion volume
Glucocorticoids	Reduces airway inflammation and mucin secretion
Macrolide antibiotics	Reduces airway inflammation and mucin secretion
Mucolytics
N-Acetylcysteine	Breaks disulphide bonds linking mucin polymers
	Antioxidant and anti-inflammatory effects
N-Acystelyn	Increases chloride secretion and breaks disulphide bonds
Erdosteine	Modulates mucus production and increases mucociliary transport
Dornase alfa	Hydrolyses the DNA in mucus and reduces viscosity in the lungs
Gelsolin	Severs actin filament cross-links
Thymosin β4	Severs actin filament cross-links
Dextran	Breaks hydrogen bonds and increases secretion hydration
Heparin	Breaks both hydrogen and ionic bonds
Mucokinetics#
Bronchodilators	Improves cough clearance by increasing expiratory flow
Surfactants	Decreases sputum/mucus adhesiveness
Ambroxol	Stimulates surfactant production and inhibits neuronal sodium channels

^#: also referred to as cough clearance promoters.