Drugs for Treating Colds

1
Drugs for Treating Colds Allergies

• Chapter 10

2
Understanding the Common Cold

• Most caused by viral infection (rhinovirus or
  influenza virusthe flu)
• Virus invades tissues (mucosa) of upper
  respiratory tract, causing upper respiratory
  infection (URI)

3
Treatment of the Common Cold

• Involves combined use of antihistamines, nasal
  decongestants, antitussives, and expectorants
• Treatment is symptomatic only, not curative
• Symptomatic treatment does not eliminate the
  causative pathogen

4
Treatment of the Common Cold - Continued

• Difficult to identify whether cause is viral or
  bacterial
• Treatment is empiric therapy, treating the most
  likely cause
• Antivirals and antibiotics may be used, but a
  definite viral or bacterial cause may not be
  easily identified

5
Antihistamines

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

6
Antihistamines - Continued

• 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

7
Antihistamines - Continued

• H2 blockers or H2 antagonists
• Used to reduce gastric acid in PUD
• Examples cimetidine, ranitidine, famotidine

8
Antihistamines - Continued

• 10 to 20 of general population is sensitive to
  various environmental allergies
• Histamine-mediated disorders
• Allergic rhinitis (hay fever, mould and dust
  allergies)
• Anaphylaxis
• Angioneurotic edema
• Drug fevers
• Insect bite reactions
• Urticaria (itching)

9
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

10
Antihistamines Mechanism of Action - Contd

• 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

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Antihistamines Mechanism of Action - Contd

• More effective in preventing the actions of
  histamine rather than reversing them
• Should be given early in treatment, before all
  the histamine binds to the receptors

12
Antihistamines Indications

• Management of
• Nasal allergies
• Seasonal or perennial allergic rhinitis (hay
  fever)
• Allergic reactions
• Motion sickness
• Sleep disorders

13
Antihistamines Indications - Continued

• Also used to relieve symptoms associated with the
  common cold
• Sneezing, runny nose
• Palliative treatment, not curative

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Antihistamines Side effects

• Anticholinergic (drying) effects, most common
• Dry mouth
• Difficulty urinating
• Constipation
• Changes in vision
• Drowsiness
• Mild drowsiness to deep sleep

15
Antihistamines Two Types

• Traditional
• Nonsedating/peripherally acting

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Traditional Antihistamines

• Older
• Work both peripherally and centrally
• Have anticholinergic effects, making them more
  effective than nonsedating agents in some cases
• Examples Benedryl (diphenhydramine)

17
Nonsedating/Peripherally Acting Antihistamines

• Developed to eliminate unwanted side effects,
  mainly sedation
• Work peripherally to block the actions of
  histamine thus, fewer CNS side effects
• Longer duration of action (increases compliance)
• Examples reactine, allegra

18
AntihistaminesAthletic Training Implications

• Instruct clients to report excessive sedation,
  confusion, or hypotension
• Avoid driving and do not consume alcohol or other
  CNS depressants
• Do not take these medications with other
  prescribed or OTC medications without checking
  with prescriber

19
AntihistaminesAT Implications - Contd

• Best tolerated when taken with mealsreduces 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

20
Decongestants
21
Nasal Congestion

• Excessive nasal secretions
• Inflamed and swollen nasal mucosa
• Primary causes
• Allergies
• Upper respiratory infections (common cold)

22
Decongestants Types - Continued

• Two dosage forms
• Oral
• Inhaled/topically applied to the nasal membranes

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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

24
Topical Nasal Decongestants

• Topical adrenergics
• Prompt onset
• Potent
• Sustained use over several days causes rebound
  congestion, making the condition worse
• EgDRISTAN DECONGESTANT NASAL MIST
  (SOLUTION)COMPOSITIONEach 1 mL of solution
  contains        Phenylephrine HCl        5
  mg        Pheniramine Maleate        2 mg

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Topical Nasal Decongestants - Continued

• Adrenergics
• desoxyephedrine
• phenylephrine
• Intranasal steroids
• beclomethasone dipropionate
• flunisolide
• fluticasone

26
Nasal DecongestantsMechanism 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

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Nasal DecongestantsMechanism of Action Contd

• 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

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Nasal Decongestants Indications

• Relief of nasal congestion associated with
• Acute or chronic rhinitis
• Common cold
• Sinusitis
• Hay fever
• Other allergies

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Nasal Decongestants Indications - Continued

• May also be used to reduce swelling of the nasal
  passage and facilitate visualization of the
  nasal/pharyngeal membranes before surgery or
  diagnostic procedures

30
Nasal Decongestants Side Effects

• Adrenergics Steroids
• Nervousness Local mucosal dryness
• Insomnia and irritation
• Palpitations
• Tremors
• (systemic effects due to adrenergic stimulation
  of theheart, blood vessels, and CNS)

31
Nasal DecongestantsAthletic Training
Implications

• Decongestants may cause hypertension,
  palpitations, and CNS stimulationavoid in
  clients with these conditions
• Clients on medication therapy for hypertension
  should check with their physician before taking
  OTC decongestants
• Assess for drug allergies

32
Nasal DecongestantsAT Implications - Contd

• Athlete should avoid caffeine and
  caffeine-containing products
• Report a fever, cough, or other symptoms lasting
  longer than a week
• Monitor for intended therapeutic effects

33
Antitussives
34
Cough Physiology

• Respiratory secretions and foreign objects are
  naturally removed by the
• Cough reflex
• Induces coughing and expectoration
• Initiated by irritation of sensory receptors in
  the respiratory tract

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Two Basic Types of Cough

• Productive cough
• Congested, removes excessive secretions
• Nonproductive cough
• Dry cough

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Coughing

• Most of the time, coughing is beneficial
• Removes excessive secretions
• Removes potentially harmful foreign substances
• In some situations, coughing can be harmful, such
  as after hernia repair surgery

37
Coughing

• Most of the time, coughing is beneficial
• Removes excessive secretions
• Removes potentially harmful foreign substances
• In some situations, coughing can be harmful, such
  as after hernia repair surgery

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Antitussives Definition

• Drugs used to stop or reduce coughing
• Opioid and nonopioid(narcotic and nonnarcotic)
• Used only for nonproductive coughs!

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Antitussives Mechanism of Action

• Opioids
• Suppress the cough reflex by direct action on the
  cough centre in the medulla
• Examples
• codeine
• hydrocodone

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Antitussives Mechanism of Action - Contd

• 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

41
Antitussives Indications

• Used to stop the cough reflex when the cough is
  nonproductive and/or harmful

42
Antitussives Side Effects

• Dextromethorphan
• Dizziness, drowsiness, nausea
• Opioids
• Sedation, nausea, vomiting, lightheadedness,
  constipation

43
Antitussive AgentsAthletic Training Implications

• Assess for allergies
• Instruct Athlete to avoid driving due to possible
  sedation, drowsiness, or dizziness
• If taking chewable tablets or lozenges, do not
  drink liquids for 30 to 35 minutes afterward

44
Antitussive AgentsAT Implications - Contd

• Report any of the following symptoms to the
  physician
• Cough that lasts more than a week
• A persistent headache
• Fever
• Rash
• Antitussive agents are for nonproductive coughs
• Monitor for intended therapeutic effects

45
Expectorants
46
Expectorants Definition

• Drugs that aid in the expectoration (removal) of
  mucus
• Reduce the viscosity of secretions
• Disintegrate and thin secretions

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Expectorants Mechanisms of Action

• Direct stimulation
• Reflex stimulation
• Final result thinner mucus that is easier to
  remove

48
Expectorants Mechanism of Action - Contd

• 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

49
Expectorants Drug Effects

• By loosening and thinning sputum and bronchial
  secretions, the tendency to cough is indirectly
  diminished

50
Expectorants Indications

• Used for the relief of nonproductive coughs
  associated with

Common cold Bronchitis Laryngitis Pharyngitis Cou
ghs caused by chronic paranasal sinusitis
Pertussis Influenza Measles
51
ExpectorantsAthletic Training Implications

• Expectorants should be used with caution in the
  older athlete or those with asthma or respiratory
  insufficiency
• Athletes taking expectorants should receive more
  fluids, if permitted, to help loosen and liquefy
  secretions
• Refer a fever, cough, or other symptoms lasting
  longer than a week
• Monitor for intended therapeutic effects