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

MUCOLYTICS Mucolytics (Table 54.5) increase or liquefy respiratory secretions to aid the clearing of the airways in high-risk respiratory people who are coughing up thick, tenacious secretions. People may be suffering from conditions such as chronic obstructive pulmonary disease (COPD), cystic fibrosis, pneumonia or tuberculosis. Mucolytics include acetylcysteine ( Mucomyst and others), brom- hexine ( Bisolvon) and dornase alfa ( Pulmozyme ). Therapeutic actions and indications Acetylcysteine is used orally to protect liver cells from being damaged during episodes of paracetamol toxicity because it normalises hepatic glutathione levels and binds with a reactive hepatotoxic metabolite of acetaminophen. Acetylcysteine affects the mucoproteins in the respira- tory secretions by splitting apart disulfide bonds that are responsible for holding the mucus material together. The result is a decrease in the tenacity and viscosity of the secretions. See Table 54.5 for usual indications. Bromhexine reduces viscosity of secretions and acti- vates ciliated epithelium, facilitating expectoration. Dornase alfa is a mucolytic prepared by recom- binant DNA techniques that selectively break down respiratory tract mucus by separating extracellular DNA from proteins. It is used in cystic fibrosis, which is characterised by thick, tenacious mucus production. See Table 54.5 for usual indications.

■ ■ Offer support and encouragement to help the person cope with the disease and the drug regimen. Evaluation ■ ■ Monitor response to the drug (improved effectiveness of cough). ■ ■ Monitor for adverse effects (skin rash, GI upset, CNS effects). ■ ■ Evaluate the effectiveness of the teaching plan (person can name drug, dosage, adverse effects to watch for, specific measures to avoid them and measures to take to increase the effectiveness of the drug). ■ ■ Monitor the effectiveness of comfort and safety measures and compliance with the regimen.

KEY POINTS

■■ Expectorants are drugs that liquefy the lower respiratory tract secretions. They are used for the symptomatic relief of respiratory conditions characterised by a dry, non-productive cough. ■■ Guaifenesin is the only expectorant currently available. Care should be taken to avoid inadvertent overdose when using OTC products that might contain this drug.

TABLE 54.5

DRUGS IN FOCUS Mucolytics

Drug name

Dosage/route

Usual indications

By nebulisation, 1–10 mL of 20% solution q 2–6 hours; by direct installation, 1–2 mL of 20% solution q 1–4 hours

Liquefaction of secretions in high- risk respiratory people who have difficulty moving secretions, including postoperative people (e.g. people with tracheostomies to facilitate airway clearance and suctioning); clearing of secretions for diagnostic tests (e.g. diagnostic bronchoscopy); used orally to protect the liver from paracetamol toxicity; treatment of atelectasis from thick mucus secretions Liquefaction of secretions in respiratory conditions where excess mucus is produced To relieve the build-up of secretions in high-risk respiratory people who have difficulty moving secretions, including postoperative people (e.g. people with tracheostomies to facilitate airway clearance and suctioning); clearing of secretions for diagnostic tests (e.g. diagnostic bronchoscopy); treatment of atelectasis from thick mucus secretions as in cystic fibrosis

acetylcysteine (Mucomyst)

bromhexine (Bisolvon)

Adults: 8 mg PO t.d.s. increased to 16 mg PO t.d.s. if required Paediatric (6–11 years): 8 mg PO t.d.s. 2.5 mg inhaled once daily through nebuliser may increase to 2.5 mg b.d. in people over 21 years

dornase alfa (Pulmozyme)