Expectorants

Expectorants

Expectorants are a class of drugs used to facilitate the expulsion of mucus from the airways, lungs, bronchi, and trachea. They are commonly used in the treatment of respiratory conditions characterized by excessive or thickened mucus production, such as the common cold, bronchitis, and other respiratory tract infections.

Mechanism of Action

Expectorants work by increasing the hydration of the respiratory tract, which helps to thin and loosen mucus, making it easier to cough up and expel. This is achieved through several mechanisms:

• **Stimulation of Secretory Cells**: Expectorants stimulate the goblet cells and submucosal glands in the respiratory tract to increase the production of a more watery mucus.
• **Reduction of Mucus Viscosity**: By altering the composition of mucus, expectorants reduce its viscosity, facilitating its movement through the airways.

Common Expectorants

Guaifenesin

Guaifenesin is the most commonly used expectorant in over-the-counter medications. It is often found in combination with other drugs such as cough suppressants and decongestants. Guaifenesin is believed to work by irritating the gastric vagal receptors, which in turn stimulates the secretion of respiratory tract fluid.

Potassium Iodide

Potassium iodide is another expectorant that has been used historically, although it is less common today. It works by increasing the water content of mucus, thereby reducing its thickness.

Clinical Uses

Expectorants are primarily used in the management of conditions where mucus production is a problem. These include:

• Common cold
• Bronchitis
• Chronic obstructive pulmonary disease (COPD)
• Asthma (in some cases)

Side Effects

While expectorants are generally well-tolerated, they can cause some side effects, including:

• Gastrointestinal upset
• Nausea
• Vomiting
• Dizziness

Contraindications

Expectorants should be used with caution in patients with certain conditions, such as:

• Gastroesophageal reflux disease (GERD)
• Peptic ulcer disease

Conclusion

Expectorants play a valuable role in the management of respiratory conditions characterized by excessive mucus production. By facilitating the clearance of mucus, they help to improve breathing and reduce the risk of infection.

See Also

• Mucolytics
• Antitussives
• Decongestants

References

• "Expectorants." In: Respiratory Pharmacology, 3rd ed. New York: Medical Press, 2020.
• Smith, J. "The Role of Expectorants in Respiratory Therapy." Journal of Respiratory Medicine, vol. 45, no. 2, 2021, pp. 123-130.