1. Drugs affecting the respiratory system
Antihistamines, Decongestants, Antitussives & Expectorants
Dr.Amira Yahia

2. Understanding the Common Cold
Most caused by viral infection (rhinovirus or influenza virus—the “flu”)
Virus invades tissues (mucosa) of upper respiratory tract, causing upper respiratory infection (URI)

3. Antihistamines
Drugs that directly compete with histamine for specific receptor sites
Two histamine receptors
H1 (histamine1)
H2 (histamine2)

4. Antihistamines (cont’d)
H1 histamine receptor- found on smooth muscle, endothelium, and central nervous system tissue; causes vasodilation, bronchoconstriction, smooth muscle activation, and separation of endothelia cellss (responsible for hives), and pain and itching due to insect stings
H1 antagonists are commonly referred to as antihistamines
Antihistamines have several properties
Antihistaminic
Anticholinergic
Sedative

5. Antihistamines (cont’d)
H2 blockers or H2 antagonists
Used to reduce gastric acid
Examples: cimetidine, ranitidine, famotidine

6. Antihistamines: Mechanism of Action
Block action of histamine at the H1 receptor sites
Compete with histamine for binding at unoccupied receptors
Cannot push histamine off the receptor if already bound

7. Antihistamines: Mechanism of Action (cont’d)
The binding of H1 blockers to the histamine receptors prevents the adverse consequences of histamine stimulation
Vasodilation
Increased GI and respiratory secretions
Increased capillary permeability

8. Antihistamines: Indications
Management of:
Nasal allergies
Seasonal or perennial allergic rhinitis (hay fever)
Allergic reactions
Motion sickness
Sleep disorders

9. Antihistamines: Indications (cont’d)
Also used to relieve symptoms associated with the common cold
Sneezing, runny nose
Palliative treatment, not curative

10. Antihistamines: Side effects
Anticholinergic (drying) effects, most common
Dry mouth
Difficulty urinating
Constipation
Changes in vision
Drowsiness
Mild drowsiness to deep sleep

11. Antihistamines: Nursing Implications
Gather data about the condition or allergic reaction that required treatment; also assess for drug allergies
Contraindicated in the presence of acute asthma attacks and lower respiratory diseases
Use with caution in increased intraocular pressure, cardiac or renal disease, hypertension, asthma, COPD, peptic ulcer disease, BPH, or pregnancy

12. Antihistamines: Nursing Implications (cont’d)
Instruct clients to report excessive sedation, confusion, or hypotension
Avoid driving or operating heavy machinery, and do not consume alcohol or other CNS depressants
Do not take these medications with other prescribed or OTC medications without checking with prescriber

13. Antihistamines: Nursing Implications (cont’d)
Best tolerated when taken with meals—reduces GI upset
If dry mouth occurs, teach client to perform frequent mouth care, chew gum, or suck on hard candy to ease discomfort
Monitor for intended therapeutic effects

14. Decongestants

15. Nasal Congestion Excessive nasal secretions
Inflamed and swollen nasal mucosa
Primary causes
Allergies
Upper respiratory infections (common cold)

16. Decongestants: Types (cont’d)
Two dosage forms
Oral
Inhaled/topically applied to the nasal membranes

17. Oral Decongestants Prolonged decongestant effects, but delayed onset
Effect less potent than topical
No rebound congestion
Exclusively adrenergics
Example: pseudoephedrine, Sinutab, Dristan, Tylenol cold, Sudafed

18. Topical Nasal Decongestants
Topical adrenergics
Prompt onset
Potent
Sustained use over several days causes rebound congestion, making the condition worse
Eg: DRISTAN* DECONGESTANT NASAL MIST (SOLUTION) COMPOSITION: Each 1 mL of solution contains:         Phenylephrine HCl        5 mg         Pheniramine Maleate        2 mg

19. Topical Nasal Decongestants (cont’d)
Adrenergics
desoxyephedrine
phenylephrine
Intranasal steroids
beclomethasone dipropionate
flunisolide
fluticasone

20. Nasal Decongestants: Mechanism of Action
Site of action: blood vessels surrounding nasal sinuses
Adrenergics
Constrict small blood vessels that supply URI structures
As a result these tissues shrink, and nasal secretions in the swollen mucous membranes are better able to drain
Nasal stuffiness is relieved

21. Nasal Decongestants: Mechanism of Action (cont’d)
Site of action: blood vessels surrounding nasal sinuses
Nasal steroids
Anti-inflammatory effect
Work to turn off the immune system cells involved in the inflammatory response
Decreased inflammation results in decreased congestion
Nasal stuffiness is relieved

22. Nasal Decongestants: Indications
Relief of nasal congestion associated with:
Acute or chronic rhinitis
Common cold
Sinusitis
Hay fever
Other allergies

23. Nasal Decongestants: Indications (cont’d)
May also be used to reduce swelling of the nasal passage and facilitate visualization of the nasal/pharyngeal membranes before surgery or diagnostic procedures

24. Nasal Decongestants: Side Effects
Adrenergics Steroids Nervousness Local mucosal dryness Insomnia and irritation Palpitations Tremors (systemic effects due to adrenergic stimulation of the heart, blood vessels, and CNS)

25. Nasal Decongestants: Nursing Implications
Decongestants may cause hypertension, palpitations, and CNS stimulation—avoid in clients with these conditions
Clients on medication therapy for hypertension should check with their physician before taking OTC decongestants
Assess for drug allergies

26. Nasal Decongestants: Nursing Implications (cont’d)
Clients should avoid caffeine and caffeine-containing products
Report a fever, cough, or other symptoms lasting longer than a week
Monitor for intended therapeutic effects

27. Antitussives

28. Antitussives: Definition
Drugs used to stop or reduce coughing
Opioid and nonopioid (narcotic and nonnarcotic)
Used only for nonproductive coughs!

29. Antitussives: Mechanism of Action
Opioids
Suppress the cough reflex by direct action on the cough centre in the medulla
Examples:
codeine
hydrocodone

30. Antitussives: Mechanism of Action (cont’d)
Nonopioids
Suppress the cough reflex by numbing the stretch receptors in the respiratory tract and preventing the cough reflex from being stimulated
Examples:
Dextromethorphan, Nyquil, Robitussin

31. Antitussives: Indications
Used to stop the cough reflex when the cough is nonproductive and/or harmful

32. Antitussives: Side Effects
Dextromethorphan
Dizziness, drowsiness, nausea
Opioids
Sedation, nausea, vomiting, lightheadedness, constipation

33. Antitussive Agents: Nursing Implications
Perform respiratory and cough assessment, and assess for allergies
Instruct clients to avoid driving or operating heavy equipment due to possible sedation, drowsiness, or dizziness
If taking chewable tablets or lozenges, do not drink liquids for 30 to 35 minutes afterward

34. Antitussive Agents: Nursing Implications (cont’d)
Report any of the following symptoms to the caregiver
Cough that lasts more than a week
A persistent headache
Fever
Rash
Antitussive agents are for nonproductive coughs
Monitor for intended therapeutic effects

35. Expectorants

36. Expectorants: Definition
Drugs that aid in the expectoration (removal) of mucus
Reduce the viscosity of secretions
Disintegrate and thin secretions

37. Expectorants: Mechanisms of Action
Direct stimulation
Reflex stimulation
Final result: thinner mucus that is easier to remove

38. Expectorants: Mechanism of Action (cont’d)
Reflex stimulation
Agent causes irritation of the GI tract
Loosening and thinning of respiratory tract secretions occur in response to this irritation
Example: guaifenesin
Direct stimulation
The secretory glands are stimulated directly to increase their production of respiratory tract fluids
Examples: iodine-containing products such as iodinated glycerol and potassium iodide

39. Expectorants: Drug Effects
By loosening and thinning sputum and bronchial secretions, the tendency to cough is indirectly diminished

40. Expectorants: Indications
Used for the relief of nonproductive coughs associated with:
Common cold
Bronchitis
Laryngitis
Pharyngitis
Coughs caused by chronic paranasal sinusitis
Pertussis
Influenza
Measles

41. Expectorants: Nursing Implications
Expectorants should be used with caution in the elderly or those with asthma or respiratory insufficiency
Clients taking expectorants should receive more fluids, if permitted, to help loosen and liquefy secretions
Report a fever, cough, or other symptoms lasting longer than a week
Monitor for intended therapeutic effects

42. Bronchodilators and Other Respiratory Agents

43. Table 36-2 Stepwise approach to the management of asthma

44. Table 36-3 Mechanisms of anti-asthmatic drug action

45. Diseases of the Lower Respiratory Tract
Bronchial asthma
Emphysema
Chronic bronchitis
COPD
Cystic fibrosis
Acute respiratory distress syndrome

46. Agents Used to Treat Asthma
Long-term control
Antileukotrienes
Cromoglycate
Inhaled steroids
Long-acting beta2-agonists
Quick relief
Intravenous systemic corticosteroids
Short-acting inhaled beta2-agonists
ipratropium
nedocromil
theophylline

47. Bronchodilators and Respiratory Agents
Xanthine derivatives
Beta-adrenergic agonists
Anticholinergics
Antileukotrienes
Corticosteroids
Mast cell stabilizers

48. Bronchodilators: Xanthine Derivatives
Plant alkaloids: caffeine, theobromine, and theophylline
Only theophylline is used as a bronchodilator
Examples:
aminophylline
Theophylline
Slo-Bid®
Uniphyl®

49. Xanthine Derivatives: Drug Effects
Cause bronchodilation by relaxing smooth muscles of the airways
Result: relief of bronchospasm and greater airflow into and out of the lungs
Also cause CNS stimulation
Slow onset action and are mostly used for prevention
Aminophylline(Status asthmaticus)

50. Xanthine Derivatives: Drug Effects (cont’d)
Also cause cardiovascular stimulation: increased force of contraction and increased HR, resulting in increased cardiac output and increased blood flow to the kidneys (diuretic effect)

51. Xanthine Derivatives: Indications
Dilation of airways in asthmas, chronic bronchitis, and emphysema
Mild to moderate cases of acute asthma
Adjunct agent in the management of COPD

52. Xanthine Derivatives: Side Effects
Nausea, vomiting, anorexia
Gastroesophageal reflux during sleep
Sinus tachycardia, extrasystole, palpitations, ventricular dysrhythmias
Transient increased urination

53. Nursing Implications: Xanthine Derivatives
Contraindications: history of PUD or GI disorders
Cautious use: cardiac disease

54. Bronchodilators: Beta-Agonists
Large group, sympathomimetics
Used during acute phase of asthmatic attacks
Quickly reduce airway constriction and restore normal airflow
Stimulate beta2-adrenergic receptors throughout the lungs

55. Bronchodilators: Beta-Agonists (cont’d)
Three types
Nonselective adrenergics
Stimulate alpha-, beta1- (cardiac), and beta2- (respiratory) receptors
Example: epinephrine
Nonselective beta-adrenergics
Stimulate both beta1- and beta2-receptors
Example: isoproterenol
Selective beta2 drugs
Stimulate only beta2-receptors
Example: salbutamol

56. Beta-Agonists: Indications
Relief of bronchospasm related to asthma, bronchitis, and other pulmonary diseases
Useful in treatment of acute attacks as well as prevention

57. Beta-Agonists: Side Effects
Beta2 (salbutamol)
Hypotension OR hypertension
Vascular headaches
Tremor
Contraindicated: clients with allergies, tachyarythmias, severe cardiac disease

58. Nursing Implications
Encourage clients to take measures that promote a generally good state of health in order to prevent, relieve, or decrease symptoms of COPD
Avoid exposure to conditions that precipitate bronchospasms (allergens, smoking, stress, air pollutants)
Adequate fluid intake
Compliance with medical treatment
Avoid excessive fatigue, heat, extremes in temperature, caffeine

59. Nursing Implications (cont’d)
Perform a thorough assessment before beginning therapy, including:
Skin colour
Baseline vital signs
Respirations (should be <12 or >24 breaths/min)
Respiratory assessment, including SaO2
Sputum production
Allergies
History of respiratory problems
Other medications

60. Nursing Implications (cont’d)
Teach clients to take bronchodilators exactly as prescribed
Ensure that clients know how to use inhalers and MDIs, and have the clients demonstrate use of devices
Monitor for side effects

61. Nursing Implications (cont’d)
Monitor for therapeutic effects
Decreased dyspnea
Decreased wheezing, restlessness, and anxiety
Improved respiratory patterns with return to normal rate and quality
Improved activity tolerance
Decreased symptoms and increased ease of breathing

62. Anticholinergics: Mechanism of Action
Acetylcholine (ACh) causes bronchial constriction and narrowing of the airways
Anticholinergics bind to the ACh receptors, preventing ACh from binding
Result: bronchoconstriction is prevented, airways dilate

63. Anticholinergics
Atrovent (ipratropium bromide) is the only anticholinergic used for respiratory disease
Slow and prolonged action
Used to prevent bronchoconstriction
NOT used for acute asthma exacerbations!
Combivent (salbutamol/ipratroprium)

64. Anticholinergics (cont’d)
Side effects:
Dry mouth or throat
Gastrointestinal distress
Headache
Coughing
Anxiety
No known drug interactions

65. Antileukotrienes Also called leukotriene receptor antagonists (LRTAs)
Newer class of asthma medications
Three subcategories of agents

66. Antileukotrienes (cont’d)
Currently available agents:
Montelukast (sold as Singulair®)
Zafirlukast (sold as Accolate®)

67. Antileukotrienes: Mechanism of Action
Leukotrienes are substances released when a trigger, such as cat hair or dust, starts a series of chemical reactions in the body
Leukotrienes cause inflammation, bronchoconstriction, and mucus production
Result: coughing, wheezing, shortness of breath

68. Antileukotrienes: Mechanism of Action (cont’d)
Antileukotriene agents prevent leukotrienes from attaching to receptors on cells in the lungs and in circulation
Inflammation in the lungs is blocked, and asthma symptoms are relieved

69. Antileukotrienes: Drug Effects
By blocking leukotrienes:
Prevent smooth muscle contraction of the bronchial airways
Decrease mucus secretion
Prevent vascular permeability
Decrease neutrophil and leukocyte infiltration to the lungs, preventing inflammation

70. Antileukotrienes: Indications
Prophylaxis and chronic treatment of asthma in adults and children older than age 12
NOT meant for management of acute asthmatic attacks
Montelukast is approved for use in children ages 6 and older

71. Antileukotrienes: Side Effects
zafirlukast
Headache
Nausea
Diarrhea
Liver dysfunction
montelukast has fewer side effects

72. Antileukotrienes: Nursing Implications
Ensure that the drug is being used for chronic management of asthma, not acute asthma
Teach the client the purpose of the therapy
Improvement should be seen in about 1 week

73. Corticosteroids Anti-inflammatory Used for chronic asthma
Do not relieve symptoms of acute asthmatic attacks
Oral or inhaled forms
Inhaled forms reduce systemic effects
May take several weeks before full effects are seen

74. Corticosteroids: Mechanism of Action
Stabilize membranes of cells that release harmful bronchoconstricting substances
These cells are leukocytes, or white blood cells
Also increase responsiveness of bronchial smooth muscle to beta-adrenergic stimulation

75. Inhaled Corticosteroids
Budesonide (Pulmicort®)
Fluticasone (Flovent®)

76. Inhaled Corticosteroids: Indications
Treatment of bronchospastic disorders that are not controlled by conventional bronchodilators
NOT considered first-line agents for management of acute asthmatic attacks or status asthmaticus

77. Inhaled Corticosteroids: Side Effects
Pharyngeal irritation
Coughing
Dry mouth
Oral fungal infections
Systemic effects are rare because of the low doses used for inhalation therapy

78. Inhaled Corticosteroids: Nursing Implications
Contraindicated in client with psychosis, fungal infections, AIDS, TB
Cautious use in clients with diabetes, glaucoma, osteoporosis, PUD, renal disease, HF, edema
Teach clients to gargle and rinse the mouth with water afterward to prevent the development of oral fungal infections

79. Inhaled Corticosteroids: Nursing Implications (cont’d)
Abruptly discontinuing these medications can lead to serious problems
If discontinuing, should be weaned for 1 to 2 weeks, only if recommended by physician
Report any weight gain of more than 2.5 kg a week or the occurrence of chest pain

80. PO corticosteroids Prednisolone (sold as Pediapred®)
Prednisone (sold as Deltasone®)

81. Combination medications
Corticosteroids
Budesonide (Pumicort®)
Formoterol (Oxeze®)
Long-Acting bronchodilator
Fluticasone (Flovent®)
Salmeterol (Severent®)

82. Mast Cell Stabilizers Cromoglycate (sold as Intal®)
Nedocromil (sold as Tilade®)
Ketotifen fumarate (sold as Zaditen®)

83. Mast Cell Stabilizers: Indications
Adjuncts to the overall management of asthma
Used solely for prophylaxis, NOT for acute asthma attacks
Used to prevent exercise-induced bronchospasm
Used to prevent bronchospasm associated with exposure to known precipitating factors, such as cold, dry air or allergens

84. Mast Cell Stabilizers: Side Effects
Coughing Sore throat Rhinitis Bronchospasm
Taste changes Dizziness Headache

85. Mast Cell Stabilizers: Nursing Implications
For prophylactic use only
Contraindicated for acute exacerbations
Not recommended for children younger than age 5
Therapeutic effects may not be seen for up to 4 weeks
Teach clients to gargle and rinse the mouth with water afterward to minimize irritation to the throat and oral mucosa

86. Inhalers: Client Education
For any inhaler prescribed, ensure that the client is able to self-administer the medication
Provide demonstration and return demonstration
Ensure the client knows the correct time intervals for inhalers
Provide a spacer if the client has difficulty coordinating breathing with inhaler activation