The Mucociliary System

• Excess mucus is a source of respiratory congestion

The role of mucus: 4 protective functions^1-4

• Acts as a barrier to infection and irritative particles
• Is a medium for the transport and removal of trapped, inhaled particles, 
  debris, dead cells, and cell products
• Provides airway humidification and warming
• Maintains an optimal environment for the action of the cilia

Key components of a clear airway^4-6

• Thin, normal mucus secretions
• Normal functioning cilia move mucus out of the lungs or sinuses
• Unobstructed drainage openings

From clear to congested: the problem with excess mucus^4,5

Normally, mucus is secreted to fulfill its protective/coating function and drains into the nasal passages. Excess or viscous mucus may cause a degenerative cycle to occur that arrests cilia and clogs sinus ostia.^1,5

Behind the symptoms: excess mucus

• Chest congestion is a symptom associated with mucus secretions when cilia and patent sinus drainage fail to promote continuous clearance of secretions¹
• Nasal congestion is associated with thick,⁷ abnormal mucus which results from swelling of the nasal and sinus membranes^1,7
• Cough is another symptom common to many upper and lower respiratory conditions. Stimulation of the cough reflex in the upper respiratory tract associated with congestion is believed to be a primary cause of cough^8,9
• Airway mucosal inflammation may be a direct response to inhaled irritants¹⁰
• Bronchopulmonary C-fiber endings and rapidly adapting pulmonary receptors (RARs) help to protect the lungs against inhaled irritants¹⁰

Mucus management: Selected treatment options^11,12

• Expectorants (eg, guaifenesin): loosen congestion in chest, making coughs more productive
• Mucolytics (eg, acetylcysteine): reduce mucus viscosity, increasing mucus flow
• Antitussives (eg, dextromethorphan): suppress the body's urge to cough
• Nasal decongestants (eg, pseudoephedrine, phenylephrine, and oxymetazoline) open up the nasal and sinus passages

References: 1. Becker DG. Sinusitis. J Long Term Eff Med Implants. 2003;13(3):175-194. 2. Desrosiers M, Klossek J-M, Benninger M. Management of acute bacterial rhinosinusitis: current issues and future perspectives. Int J Clin Pract. 2006;60(2):190-200. 3. Merck Manual Home Edition Web site. Defenses against infection. http://www.merck.com/mmhe/sec17/ch188/ch188d.html?qt=mucus&alt=sh. Accessed February 21, 2011. 4. Data on file [Mucinex® Training Manual], Reckitt Benckiser, Parsippany, NJ. 5. Taghizadeh F, Hadley JA, Osguthorpe JD. Pharmacological treatments for rhinosinusitis. Expert Opin Pharmacother. 2002;3(3):305-313. 6. Winstead W. Rhinosinusitis. Prim Care Clin Office Pract. 2003;30:137-154. 7. Connell JT, Linzmayer MI. Comparison of nasal airway patency changes after treatment with oxymetazoline and pseudoephedrine. Am J Rhinology. 1987;1(2):87-94. 8. National Lung Health Education Program Web site. Chronic cough. http://www.nlhep.org/books/pul_Pre/chronic-cough.html. Accessed February 21, 2011. 9. Dicpinigaitis PV, Gayle YE. Effect of guaifenesin on cough reflex sensitivity. Chest. 2003;124:2178-2181. 10. Lee L-Y, Widdicombe JG. Modulation of airway sensitivity to inhaled irritants: role of inflammatory mediators. http://www.ehponline.org/members/2001/suppl-4/585-589lee/lee-full.html. 11. Familydoctor.org Web site. OTC medicines and how they work. http://familydoctor.org/online/famdocen/home/otc-center/basics/otc.printerview.html. Accessed February 21, 2011. 12.Dorland's Illustrated Medical Dictionary, 30th ed. Philadelphia. PA: Saunders; 2003:469, 656, 1179.