CHAPTER 38
DRUGS FOR ALLERGIC RHINITIS AND THE COMMON COLD
LEARNING OUTCOME 1
Identify major functions of the upper respiratory tract.
Concepts
The upper respiratory tract warms, humidifies, and cleans incoming air. The upper respiratory tract traps
particulate matter and many pathogens, preventing them from being carried to bronchioles and alveoli. The
nasal mucosa is richly supplied with vascular tissue and is controlled by the autonomic nervous system. This
first line of immunological defense incorporates ciliated epithelium, nasal mucus, and the mast cells that line the
nasal mucosa to protect the body. The respiratory tract provides the body with the oxygen critical for all cells to
carry on normal activities. The respiratory system also provides a means by which the body can rid itself of
excess acids and bases.
Figure 38-1 The Respiratory System
LEARNING OUTCOME 2
Describe common causes and symptoms of allergic rhinitis.
Concepts
Allergic rhinitis or hay fever is inflammation of the nasal mucosa resulting from exposure to allergens. Allergic
rhinitis is characterized by sneezing, watery eyes, and nasal congestion. It is caused by exposure to an antigen
(allergen), which causes histamine release. The most common allegens include: pollens from weeds, grasses,
and trees; mold spores; dust mites; certain foods; and animal dander. Chemical fumes, tobacco smoke, or air
pollutants such as ozone are nonallergenic factors that may worsen symptoms. Pharmacotherapy is targeted at
preventing the disorder or relieving its symptoms. (Figure 38.2 illustrates the mechanism of allergic rhinitis.)
Figure 38.2 Mechanism of Allergic Rhinitis
LEARNING OUTCOME 3
Differentiate between H1 and H2 histamine receptors.
Concepts
Histamine is a chemical mediator of the inflammatory response. H1 histamine receptors are found in the smooth
muscle of the vascular system and bronchial tree and are responsible for many of the symptoms of allergic
rhinitis. The other major histamine receptor, H2, is found in the gastric mucosa and is responsible for peptic
ulcers.
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LEARNING OUTCOME 4
Compare and contrast the oral and intranasal decongestants.
Concepts
1. Intranasal glucocorticoids have become drugs of choice in treating allergic rhinitis due to their high
efficacy and wide margin of safety. For maximum effectiveness, they must be administered 2 to 3 weeks
prior to allergen exposure. Intranasal glucocorticoids decrease the secretion of inflammatory mediators,
reduce tissue edema, and cause mild vasoconstriction. Alternative therapy is with mast cell stabilizers such
as intranasal cromolyn (Nasalcrom). (See Table 38.3.)
2. The most commonly used decongestants are oral and intranasal sympathomimetics, which alleviate the
nasal congestion associated with allergic rhinitis and the common cold. (See Table 38.4.)
3. Intranasal drugs are more efficacious but should only be used for 3 to 5 days due to rebound congestion.
Intranasal preparations are available over the counter in sprays and drops. They affect a local action within
minutes and have few systemic effects.
4. Oral preparation decongestants have more systemic effects, response time is slower, and they are less
effective at relieving severe congestion. These drugs are often combined with antihistamine preparations.
Table 38.3 Intranasal Glucocorticoids
Table 38.4 Nasal Decongestants
LEARNING OUTCOME 5
Discuss the pharmacotherapy of cough.
Concepts
1. Cough is a natural reflex mechanism that serves to forcibly remove excess secretions and foreign material
from the respiratory system. Common colds and allergies create cough. Antitussives are effective at
relieving cough due to the common cold. Opioids are used for severe cough. Nonopioids such as
dextromethorphan are used for mild or moderate cough. (See Table 38.5.)
2. Expectorants promote mucus secretion, making it thinner and easier to remove by coughing. Mucolytics
directly break down mucous molecules.
Table 38.5 Selected Antitussives and Expectorants
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LEARNING OUTCOME 6
Describe the role of expectorants and mucolytics in treating bronchial congestion.
Concepts
1. Expectorants are drugs that reduce the thickness or viscosity of bronchial secretions. They increase mucus
flow that can then be removed more easily by coughing. The most effective OTC expectorant is
guaifenesin (Mucinex, Robitussin, others). Guaifenesin has fewer adverse effects and is a common
ingredient in many OTC multisymptom cold and flu preparations. It is most effective in treating dry,
nonproductive cough, but may also be of benefit for patients with productive cough.
2. Mucolytics break down the chemical structure of mucus molecules. Mucolytics help loosen thick bronchial
secretions. The mucus becomes thinner, and can be removed more easily by coughing. Acetylcysteine is
delivered by the inhalation route and is used in patients who have cystic fibrosis, chronic bronchitis, or
other diseases that produce large amounts of thick bronchial secretions. Mucomyst can trigger
brochospasm and has an offensive odor resembling rotten eggs. A second mucolytic, dornase alfa
(Pulmozyme), is approved for maintenance therapy in the management of thick bronchial secretions.
Dornase alfa breaks down DNA molecules in the mucus, causing it to become less viscous. These agents
are listed in Table 38.5.
Table 38.5 Selected Antitussives and Expectorants
LEARNING OUTCOME 7
For each of the classes listed in Drugs at a Glance, know representative drugs, and explain their mechanism of
drug action, primary actions on the respiratory system, and important adverse effects.
Concepts
1. H1 Receptor Antagonists (Antihistamines). Prototype drug: diphenhydramine (Benadryl). Mechanism of
action: as a histamine (H1) receptor blocker (first generation). Primary use: to treat minor symptoms of
allergy and the common cold, such as sneezing, runny nose, and tearing of the eyes. Adverse effects:
drowsiness—occasionally, paradoxical CNS stimulation and excitability will be observed, rather than
drowsiness. Anticholinergic effects such as dry mouth, tachycardia, and mild hypotension occur in some
patients. Diphenhydramine may cause photosensitivity. (See Table 38.1.)
2. H1 Receptor Antagonists (Antihistamines). Prototype drug: fexofenadine (Allegra). Mechanism of
action: as a histamine (H1) receptor blocker (second generation). Primary use: most effective when taken
before symptoms develop. It reduces the severity of nasal congestion, sneezing, and tearing of the eyes.
Adverse effects: drowsiness (less than first-generation H1 blockers), headache, and upset stomach. (See
Table 38.2.)
3. Intranasal Glucocorticoids. Prototype drug: fluticasone (Flonase). Mechanism of action: decreases local
inflammation in the nasal passages, thus reducing nasal stuffiness. Primary use: to treat seasonal allergic
rhinitis. Adverse effects: nasal irritation and epistaxis. (See Table 38.3.)
4. Decongestants. Prototype drug: oxymetazoline (Afrin). Mechanism of action: stimulates alpha-adrenergic
receptors in the sympathetic nervous system. This causes arterioles in the nasal passages to constrict, thus
drying the mucous membranes. Primary use: to treat nasal congestion. Adverse effects: rebound
congestion, which is common when oxymetazoline is used for longer than 3 to 5 days. Minor stinging and
dryness in the nasal mucosa may be experienced. (Table 38.4.)
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5. Antitussives. Prototype drug: dextromethorphan (Delsym, Robitussin). Mechanism of action: acts in the
medulla to inhibit cough reflex. Primary use: as a component in most OTC severe cold and flu
preparations. Adverse effects: dizziness, drowsiness, and GI upset. (See Table 38.5.)
Table 38.1 H1 Receptor Antagonists
Table 38.2 Selected Antihistamine Combinations Available OTC for Allergic Rhinitis
Table 38.3 Intranasal Glucocorticoids
Table 38.4 Nasal Decongestants
Table 38.5 Selected Antitussives and Expectorants
Table 38.6 Selected Opioid Combination Drugs for Severe Cold Symptoms
Prototype Drug
 diphenhydramine (Benadryl)
 fexofenadine (Allegra)
 fluticasone (Flonase)
 oxymetazoline (Afrin)
 dextromethorphan (Benylin)
ANIMATIONS AND VIDEOS
 Mechanism in Action: Diphenhydramine (Benadryl, others)
LEARNING OUTCOME 8
Use the nursing process to care for patients who are receiving pharmacotherapy for allergic rhinitis and the
common cold.
Concepts
1. Patients Receiving Antihistamine Therapy—Assessment: Obtain a complete health history including
previous history of symptoms and association to seasons, foods, or environmental exposures, existing
cardiovascular, respiratory, hepatic, renal, or neurologic disease, glaucoma, prostatic hypertrophy or
difficulty with urination, presence of fever or active infections, pregnancy or breast-feeding, alcohol use, or
smoking. Obtain drug history noting type of adverse reaction or allergy, and possible drug interactions.
Assess for any recent changes in diet, soaps including laundry detergent or softener, cosmetics, lotions,
environment, or recent carpet-cleaning, particularly in infants and young children if allergy symptoms are of
new onset. Obtain baseline ECG and vital signs, especially pulse rate and rhythm. Assess for adverse
effects: dizziness, drowsiness, dry mouth, blurred vision, or headache. Evaluate appropriate laboratory
findings (e.g., CBC, hepatic and renal labs). Assess respiratory status and breathing pattern. Assess
neurologic status and level of consciousness. Report immediately any increasing fever, confusion, muscle
weakness, tachycardia, palpitations, hypotension, syncope, dyspnea, pulmonary congestion, urinary
retention, sudden severe eye pain or rainbow halos around lights.
2. Patients Receiving Antihistamine Therapy—Nursing diagnoses: Ineffective Airway Clearance;
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Ineffective Breathing Pattern; Disturbed Sleep Pattern, related to adverse drug effects; Fatigue; Deficient
Knowledge (drug therapy); Risk for Injury; Risk for Falls, related to adverse drug effects.
3. Patients Receiving Antihistamine Therapy—Planning: The patient will experience therapeutic effects
(e.g., decreased nasal congestion and drainage, decreased eye watering and itching); be free from or
experience minimal adverse effects. Verbalize an understanding of the drug’s use, adverse effects, and
required precautions. Demonstrate proper self-administration of the medication (e.g., dose, timing, when to
notify provider).
4. Patients Receiving Antihistamine Therapy—Implementation: Start therapy before beginning of allergy
season and appearance of symptoms. Ensure patient safety, especially in the elderly. Monitor ambulation
until effects of drug are known. Auscultate breath sounds before administering. Use with extreme caution in
patients with asthma, COPD, and a history of cardiovascular disease. Keep resuscitative equipment
accessible. Monitor vital signs especially pulse rate and rhythm (including ECG) for patients with existing
cardiac disease before administering. Monitor for persistent dry cough, increasing cough severity, increasing
congestion, or dyspnea. Monitor thyroid function. Use with caution in patients with a history of
hyperthyroidism. Monitor for vision changes. Use with caution in patients with: narrow-angle glaucoma,
history of kidney or urinary-tract disease, diabetes mellitus, history of seizure disorder; history of
hyperthyroidism. Monitor neurologic status, especially LOC. Assess for urinary retention, especially in
males over 40 or with a history of prostatic hypertrophy. Observe for signs of renal toxicity. Measure intake
and output. Monitor periodic hepatic and renal function labs, especially in patients on long-term
antihistamine use or those with previous history of hepatic or renal impairment. Monitor serum-glucose
levels with increased frequency. Use with caution in patients with a history of GI disorders, especially
peptic ulcers or liver disease. Monitor for GI side effects. Monitor for side effects, such as dry mouth;
observe for signs of anticholinergic crisis. Instruct patient and/or family in proper self-administration of
drug.
5. Patients Receiving Antihistamine Therapy—Evaluation: The patient will experience therapeutic effects
(e.g., decreased nasal congestion and drainage, decreased eye watering and itching); be free from or
experience minimal adverse effects. Verbalize an understanding of the drug’s use, adverse effects, and
required precautions. Demonstrate proper self-administration of the medication (e.g., dose, timing, when to
notify provider).
6. Patients Receiving Symptomatic Cold Relief: Antitussive, Nasal Decongestant, and Expectorant
Therapy—Assessment: Obtain a complete health history, including previous history and length of
symptoms, existing cardiovascular, respiratory, hepatic, or renal disease, presence of fever, pregnancy or
breast-feeding, alcohol use, or smoking; data on anaphylaxis, asthma, or and allergies, drug history, and
possible drug interactions. Evaluate appropriate laboratory findings (e.g., CBC, hepatic and renal labs).
Obtain vital signs, especially pulse rate and rhythm in patients with existing cardiac disease. Assess for
adverse effects: dizziness, drowsiness, blurred vision, headache, epistaxis.
7. Patients Receiving Symptomatic Cold Relief: Antitussive, Nasal Decongestant, and Expectorant
Therapy—Nursing diagnoses: Ineffective Airway Clearance; Ineffective Breathing Pattern; Disturbed
Sleep Pattern, related to somnolence or agitation; Deficient Knowledge (drug therapy); Risk for Injury,
related to adverse drug effects; Risk for Injury, related to adverse drug effects; Risk for Falls, related to
adverse drug effects.
8. Patients Receiving Symptomatic Cold Relief: Antitussive, Nasal Decongestant, and Expectorant
Therapy—Planning: The patient will experience therapeutic effects (e.g., decreased nasal congestion and
drainage, increased ease in expectorating mucus, thinner secretions, breath sounds clear). Be free from, or
experience minimal adverse effects. Verbalize an understanding of the drug’s use, adverse effects and
required precautions. Demonstrate proper self-administration of the medication (e.g., dose, timing, when to
notify provider).
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9. Patients Receiving Symptomatic Cold Relief: Antitussive, Nasal Decongestant, and Expectorant
Therapy—Implementation: Monitor for persistent dry cough, increasing cough severity, increasing
congestion, or dyspnea. Assess color and consistency of any expectorated sputum. Monitor for GI effects.
Use decongestant nasal spray first followed in 5 to 10 minutes by the glucocorticoid. Instruct patient and/or
family in proper self-administration of drug. Auscultate breath sounds before administering. Use with
extreme caution in patients with: asthma, COPD, and a history of cardiovascular disease. Keep resuscitative
equipment accessible. Monitor vital signs especially pulse rate and rhythm. Monitor for vision changes. Use
with caution in patients with: narrow-angle glaucoma, history of kidney or urinary-tract disease, diabetes
mellitus, history of seizure disorder, history of hyperthyroidism. Monitor neurologic status, especially LOC.
Observe for signs of renal toxicity. Measure intake and output. Monitor serum- glucose levels with
increased frequency. Monitor for GI side effects. Use with caution in patients with a history of GI disorders,
especially peptic ulcers or liver disease. Monitor for side effects, such as dry mouth; observe for signs of
anticholinergic crisis. Report immediately any increasing fever, tachycardia, palpitations, syncope, dyspnea,
pulmonary congestion, or confusion.
10. Patients Receiving Symptomatic Cold Relief: Antitussive, Nasal Decongestant, and Expectorant
Therapy—Evaluation: The patient will experience decreased nasal congestion and drainage, increased
ease in expectorating mucus, thinner secretions, clear breath sounds; be free from or experience minimal
adverse effects. Verbalize an understanding of the drug’s use, adverse effects and required precautions.
Demonstrate proper self-administration of the medication (e.g., dose, timing, when to notify provider).
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