Mucoactive agents are a class of chemical agents that aid in the clearance of

mucus Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It ...

or sputum from the upper and lower airways, including the

lungs The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of ...

, bronchi, and

trachea The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air-breathing animals with lungs. The trachea extends from th ...

. Mucoactive drugs include expectorants, mucolytics, mucoregulators, and mucokinetics. These medications are used in the treatment of respiratory diseases that are complicated by the oversecretion or

inspissation Inspissation is the process of thickening by dehydration. Intentional use Inspissation is the process used when heating high-protein containing media; for example to enable recovery of bacteria for testing. Once inspissation has occurred, any stain ...

of mucus. These drugs can be further categorized by their mechanism of action.

Mechanism of action

Mucoactive agents - expectorants – include mucolytics, secretolytics and mucokinetics (also called secretomotorics) * Mucolytics – thin (reduce the viscosity of) mucus * Secretolytics – increase airway water or the volume of airway secretions * Mucokinetics – increase mucociliary transport (clearance) and transportability of mucus by cough * Mucoregulators – suppress underlying mechanisms of mucus hypersecretion Alternatively, attacking the affinity between secretions and the biological surfaces is another avenue, which is used by abhesives and surfactants. Any of these effects could improve airway clearance during coughing. In general, clearance ability is hampered by the bonding to surfaces (stickiness) and by the

viscosity The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inte ...

of mucous secretions in the lungs. In turn, the viscosity is dependent upon the concentration of mucoprotein 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 Latin ''expectorare'', 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. One mucoactive agent, guaifenesin, has anxiolytic 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. This in turn can lower the viscosity by altering the

mucin Mucins () are a family of high molecular weight, heavily glycosylated proteins ( glycoconjugates) produced by epithelial tissues in most animals. Mucins' key characteristic is their ability to form gels; therefore they are a key component in m ...

-containing components.

Mucoactive drugs

Many mucoactive drugs are available, including sodium citrate or potassium citrate, potassium iodide, guaifenesin, tolu balsam, vasaka, ammonium chloride, acetylcysteine, ambroxol, bromhexine, carbocisteine, erdosteine, mecysteine, and dornase alfa.

References

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External links

National Center for Biotechnology Information
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