Mucoactive agents are a class of chemical agents that aid in the clearance ofmucus orsputum from the upper and lower airways, including thelungs,bronchi, andtrachea. Mucoactive drugs include expectorants, mucolytics, mucoregulators, and mucokinetics. These medications are used in the treatment of respiratory diseases that are complicated by the oversecretion orinspissation of mucus. These drugs can be further categorized by theirmechanism of action.[1][2]
Mucoactive agents—expectorants—include mucolytics, secretolytics and mucokinetics (also called secretomotorics)[3]
Alternatively, attacking the affinity between secretions and the biological surfaces is another avenue, which is used byabhesives andsurfactants.[citation needed]
Any of these effects could improve airway clearance during coughing.[citation needed]
In general, clearance ability is hampered by the bonding to surfaces (stickiness) and by theviscosity of mucous secretions in the lungs. In turn, the viscosity is dependent upon the concentration ofmucoprotein in the secretions.
Mucolytics, secretolytics and secretomotorics are different types of medication, yet they are intended to promote drainage of mucus from the lungs.
An expectorant (from the Latinexpectorare, to expel or banish) works by signaling the body to increase the amount or hydration of secretions, resulting in more, yet clearer, secretions and lubricating the irritated respiratory tract.[4]One mucoactive agent,guaifenesin, hasanxiolytic and muscle-relaxing properties. It is commonly available in cough syrups and also as sustained-release tablets.
Mucolytics can dissolve thick mucus and are usually used to help relieve respiratory difficulties. They do this by breaking down the chemical bonds between molecules in the mucus.[5] This in turn can lower the viscosity by altering themucin-containing components.[citation needed]
An expectorant increases bronchial secretions and mucolytics help loosen thick bronchial secretions. Expectorants reduce the thickness or viscosity of bronchial secretions, thus increasing mucus flow that can be removed more easily through coughing. Mucolytics break down the chemical structure of mucus molecules. The mucus becomes thinner and can be removed more easily through coughing.
— Adams, Holland, & Bostwick, 2008, p. 591
Mucoactive drugs include:
