McKenna's Pharmacology for Nursing, 2e

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C H A P T E R 5 4 Drugs acting on the upper respiratory tract

D rugs that affect the respiratory system work to keep the airways open and gases moving efficiently. The classes discussed in this chapter mainly act on the upper respiratory tract. Figure 54.1 shows structures of the upper respiratory tract. Figure 54.2 displays the sites of action of these drugs.

ANTITUSSIVES Antitussives are drugs that suppress the cough reflex (Table 54.1). Many disorders of the respiratory tract, including the common cold, sinusitis, pharyngitis and pneumonia, are accompanied by an uncomfortable, unproductive

Frontal sinus

Sphenoid sinus

Adenoids (pharyngeal tonsils)

Superior turbinate Middle turbinate Inferior turbinate Nose Nares

Nasopharynx

Larynx (voice box) Oesophagus Laryngopharynx Oropharynx Opening to eustachian tube

Tongue Lingual tonsils

Epiglottis Vocal cord Glottis

FIGURE 54.1  Structures of the upper respiratory tract.

Medullary cough centre

Codeine, dextromethorphan work here

Topical nasal decongestants, nasal steroid work here

Mucolytics work here

Inhaled steroids work here

Mucus

Guaifenesin works here

Antihistamines work here

Bronchodilators work here

Lung surfactants work here

FIGURE 54.2  Sites of action of drugs acting on the upper respiratory tract.

Alveoli