Introduction
Expectorants are drugs that facilitate the expulsion of mucus from the respiratory tract by increasing the production of mucus and/or reducing its viscosity.
They are used to treat coughs and congestion associated with common colds, bronchitis, and other respiratory illnesses.
Classification of Expectorants
Expectorants can be classified into two main categories:
1) Direct-acting expectorants:
These agents act directly on the secretory cells of the respiratory tract, increasing the secretion of mucus and/or decreasing its viscosity.
This increased mucus production and thinning of mucus help to facilitate its removal from the respiratory tract, ultimately making it easier to cough up.
Examples
A. Guaifenesin (glyceryl guaiacolate)
B. Iodides (e.g., potassium iodide)
C. Bromhexine
2) Indirect-acting expectorants:
These agents work by irritating the gastric mucosa, which in turn stimulates a reflex increase in respiratory tract secretions.
The increased secretions help to loosen and thin the mucus in the respiratory tract, making it easier to cough up.
Examples
A. Ammonium chloride
B. Potassium citrate
C. Sodium citrate
Cough and its type
Cough is a reflex action that helps clear the respiratory tract of mucus, irritants, and foreign particles.
It is a vital protective mechanism that helps keep the airways clear and maintain proper respiratory function.
Coughs can be classified into several types based on their duration, the nature of the cough, and the underlying cause:
1) Acute cough:
Lasts less than 3 weeks.
Often due to viral infections or irritants.
2) Subacute cough:
Lasts between 3 and 8 weeks.
May result from lingering infections or other causes.
3) Chronic cough:
Lasts more than 8 weeks.
Caused by various underlying conditions.
4) Productive cough:
Produces mucus or phlegm.
Common in respiratory infections or conditions with increased mucus production.
5) Dry (non-productive) cough:
No mucus production.
Can be caused by viral infections, allergies, irritants, or medications.
6) Nocturnal cough:
Occurs predominantly at night.
Caused by factors like asthma, postnasal drip, or GERD.
7) Whooping cough (pertussis):
Severe, uncontrollable coughing caused by Bordetella pertussis infection.
Dangerous for infants and young children.