Mucus-controlling drug therapy
The mucociliary protective system
The self-renewing, self-cleansing mucociliary escalator is one of the major defense mechanisms of the lung.
Many respiratory diseases are associated with an impaired function of the mucociliary system.
Regardless of its location, mucus is a protective factor, including lubrication, waterproofing and protection
against osmotic or inflammatory changes.
The term "mucolytic" has been replaced with "mucoactive agents".
To prevent and reduce accumulation of airway secretions, thus improving pulmonary function and gas exchange.
To prevent repeated infection and airway damage.
Some diseases in which MA therapy is indicated are cystic fibrosis, bronchiectasis, acute and chronic bronchitis
and pneumonia (mucus hypersecretion and poor clearance are common factors).
Nevertheless, the best mucus thinner is water.
Factors affecting mucociliary transport
Transport rates are slower in:
Endotracheal suctioning and tracheostomy
Hyperoxia and hypoxia
Milk doesn’t increase phlegm production
congestion in the respiratory tract.
Nature of the mucus secretion
Mucus hypersecretion (bronchorrhea) is the production of watery sputum of 100 ml or more per day.
Mucus is a threadlike strand consisting of a protein backbone to which carbohydrate side chains are attached.
Mucus is transparent; a green-yellow sputum means infection (cellular breakdown caused by the action of the
Therapeutic options for controlling mucus hypersecretion
Remove causative factors whenever possible:
- Treat infections
- Stop smoking
- Avoid pollution and allergens
Optimize tracheobronchial clearance:
- Use of bronchodilators
- Bronchial hygiene measures (deep breathing, cough and postural drainage)
- Airflow improvement by exercise and proper nutrition.
- Treat infection
- Use of corticosteroids
Use mucoactive agents (N-Acetyl L-Cysteine and Dornase alfa) as specifically indicated.
- Treatment of conditions associated with viscous mucus secretions.
- As an antidote (antioxidant) for acetaminophen overdose.
Mode of action:
Acetylcisteine disrupts the structure of the mucus molecule by substituting its own sulfhydryl groups for
the disulfide bonds in the mucus molecule. (Figure 9.9, p. 179)
Brand name: Mucomyst
Dosage forms Administration
SVN 20% 3-5 ml tid-qid
SVN 10% 6-10 ml tid-qid*
either % 1-2 ml via direct instillation
*not efficiently nebulized by the typical gas- powered, hand-held disposable nebulizer.
Bronchospasm. It is more frequent in patients with
hyperreactive airways (ex. asthma) and can be
lessened by using the 10% solution and by
concomitant use of a bronchodilator, either mixed or
Other side effects include stomatitis, nausea or
vomiting and rhinorrhea. Highly concentrated
residues by the end of the nebulization should be
avoided by rediluting with sterile water.
with antibiotics in mixture:
Other clinical uses:
Antidote for Acetaminophen overdose
Antioxidant for ARDS and lung cancer prevention
Dornase alfa is a clone of the natural
human DNAse I enzyme, which digests
Management of cystic fibrosis, to reduce the
frequency of infections and to improve or
preserve pulmonary function.
Mode of action:
DA breaks down DNA molecules found in infected
mucus. It has no action in uninfected mucus.
Dosage and administration:
DA is available as an ampule containing 2.5 mg in
2.5 ml. Daily dosing schedule is 2.5 mg a day. The
solution is to be refrigerated and protected from light.
Only approved nebulizers should be used for DA
Other side effects are less common