Generic and Brand Names
- Expectorants
- guaifenesin (Mucinex)
- Mucolytic
- acetylcysteine (Mucomyst)
- dornase alfa (Pulmozyme)
Disease Spotlight: Chronic Obstructive Pulmonary Disease
COPD is a permanent, chronic obstruction of the airways, usually tied to cigarette smoking. It bundles two related disorders, emphysema and chronic bronchitis, both of which obstruct airflow on expiration and leave the lungs overinflated with poor gas exchange. Emphysema is loss of elastic lung tissue and destruction of alveolar walls, so the alveoli hyperinflate and tend to collapse on expiration. Chronic bronchitis is permanent airway inflammation with mucus secretion, edema, and impaired postinflammatory defenses.
Expectorants
Expectorants increase a productive cough to clear the airways. They reduce the adhesiveness and surface tension of respiratory tract fluids, dropping the viscosity of those secretions so the patient moves them up and out more easily. Because they fill so many OTC preparations, patients reach for them without ever talking to a provider.
Indication is narrow: symptomatic relief of respiratory conditions marked by a dry, nonproductive cough.
Pharmacokinetics
Guaifenesin is rapidly absorbed, onset 30 minutes, duration 4 to 6 hours.
Contraindications and Cautions
Do not use with a known allergy to the drug (hypersensitivity). Use caution in pregnancy and lactation given potential effects on the fetus or infant. Do not use for a persistent cough, which can signal an underlying problem that needs evaluation.
Adverse Effects
GI: nausea, vomiting, anorexia. CNS: headache, dizziness. Respiratory: rhinorrhea, bronchospasm. Skin: rash. The one that matters most is the cough itself: prolonged OTC use can mask symptoms of a serious underlying disorder, so always chase down why the patient is coughing.
Mucolytics
Mucolytics liquefy respiratory secretions so high-risk patients coughing up thick, tenacious mucus can clear their airways. Acetylcysteine splits the disulfide bonds holding mucoproteins together, which drops the tenacity and viscosity of the secretions. Dornase alfa, made by recombinant DNA technique, selectively breaks down respiratory tract mucus by separating extracellular DNA from proteins. Acetylcysteine has a second, unrelated use: it is the antidote for acetaminophen toxicity, protecting liver cells by replenishing hepatic glutathione and binding the reactive hepatotoxic metabolite, and it is close to 100% effective when given within 8 hours of ingestion (N-Acetylcysteine, StatPearls).
Indications: liquefy secretions in high-risk patients who struggle to move them (including postop patients and those with tracheostomies, to ease airway clearance and suctioning); clear secretions for diagnostic tests such as bronchoscopy; oral use to protect the liver in acetaminophen toxicity; and treat atelectasis caused by thick mucus.
Pharmacokinetics
Mucolytics are given by nebulization or by direct instillation into the trachea through an endotracheal tube or tracheostomy.
Contraindications and Cautions
Use caution with acute bronchospasm, peptic ulcer, and esophageal varices, because the increased secretions can worsen the problem.
Adverse Effects
GI: nausea, vomiting, anorexia. CNS: headache, dizziness. Respiratory: rhinorrhea, bronchospasm. Skin: rash. As with expectorants, prolonged OTC use can hide the cause of an underlying cough.
Nursing Considerations
Nursing Assessment
Screen for contraindications and cautions: drug allergy; a persistent cough from smoking, asthma, or emphysema; and a very productive cough that points to a problem needing evaluation. Get a baseline physical to judge drug effect and catch adverse reactions: check skin for lesions and color, monitor temperature for underlying infection, listen to respirations and adventitious sounds, watch orientation and affect for CNS effects, and track blood pressure and pulse for cardiac response.
Nursing Diagnosis and Care Planning
Acute pain related to GI, CNS, or skin effects. Disturbed sensory perception (kinesthetic) related to CNS effects. Deficient knowledge regarding drug therapy. Ineffective airway clearance related to bronchospasm.
Nursing Implementation with Rationale
For expectorants, the central teaching point is duration: do not use longer than 1 week, and seek care if the cough persists past that, so an underlying condition gets evaluated and treated. Advise small, frequent meals to ease GI discomfort. Tell patients to avoid driving or dangerous tasks if dizziness or drowsiness occurs. Warn that these drugs hide in OTC products, so they must avoid stacking doses. Teach the drug name and dosage, how to limit adverse effects, warning signs, and the need for periodic monitoring, and offer support for coping with both the disease and the regimen.
For mucolytics, do not combine other drugs in the nebulizer (precipitates form and either drug can lose effect). Dilute concentrate with sterile water for injection if buildup threatens delivery. With acetylcysteine by face mask, wipe residue off the mask and the face with plain water to prevent skin breakdown. Review nebulizer use with patients taking dornase alfa at home. Store the drug in the refrigerator, protected from light. Remind cystic fibrosis patients on dornase alfa to continue all their other CF therapies, because dornase alfa is given in conjunction with standard therapy to improve pulmonary function and, in patients with an FVC at least 40% of predicted, to reduce the risk of respiratory infections needing IV antibiotics; it does not replace the rest of the regimen (Pulmozyme, FDA prescribing information). Provide the same full teaching and support as above.
Evaluation
Monitor the response (improved, more effective cough), watch for adverse effects (rash, GI upset, bronchospasm, CNS effects), confirm the patient can state the drug, dosage, and adverse effects to watch for, and check compliance and the comfort and safety measures.
Frequently Asked Questions
What is the difference between an expectorant and a mucolytic? An expectorant such as guaifenesin thins lower respiratory secretions and lowers their viscosity so a patient with a dry, nonproductive cough can finally bring something up. A mucolytic such as acetylcysteine or dornase alfa chemically breaks mucus apart so high-risk patients with thick, tenacious secretions (COPD, cystic fibrosis, pneumonia) can clear their airways. Different mechanism, different patient.
Is guaifenesin actually effective? Guaifenesin is the only expectorant available in the United States and is widely used in OTC cough products, but the evidence for symptom benefit is limited, which is exactly why the main nursing job is teaching. Patients overuse it, stack it across multiple OTC products, and let it mask a cough that needs a real workup.
How long should a patient take an OTC expectorant before seeing a provider? Do not use it for longer than about a week. A cough that persists past that can signal an underlying condition that needs evaluation, and continued OTC use only hides it.
Why is acetylcysteine also used for acetaminophen overdose? Acetylcysteine replenishes hepatic glutathione and binds the toxic acetaminophen metabolite, which protects liver cells. As the antidote for acetaminophen toxicity it is close to 100% effective when given within 8 hours of ingestion, a use entirely separate from its mucolytic action (N-Acetylcysteine, StatPearls).
What is special about giving a mucolytic by nebulizer? Do not mix other drugs in the nebulizer, because precipitates can form and either drug can lose effect. After acetylcysteine by face mask, wipe residue off the mask and the skin with plain water to prevent breakdown. Dornase alfa is refrigerated and protected from light.
Does dornase alfa cure cystic fibrosis? No. It is given alongside standard CF therapy to improve pulmonary function and, in patients with an FVC at least 40% of predicted, to lower the risk of respiratory infections needing IV antibiotics. Patients must keep up all their other CF treatments (Pulmozyme, FDA prescribing information).