Drugs for Pulmonary Disorders

1
Drugs for Pulmonary Disorders

• Chapter 25

2
Introduction

• A mere 5 to 6 minutes without breathing may
  result in death.
• The respiratory system provides the body with the
  oxygen critical for all cells to function.

3
AP

• The physiology of the respiratory system involves
  two main processes ventilation and respiration
• Primary function to bring oxygen into the body
  and to remove carbon dioxide

4
AP

• Respirationthe process by which gasses are
  exchanged
• Ventilationthe process of moving air into and
  out of the lungs
• Inspiration
• Diaphragm contracts, lowers in position
• Requires energy for contraction
• Air drawn into lungs
• Expiration
• Diaphragm relaxes, raises in position
• No energy required
• Air leaves lungs passively

5
AP

• Occurs 12-18 times per min.
• Rate controlled by neurons in the brain stem
• Modified by emotions, fever, stress, pH of blood.

6
AP

• Pathway of air entering the respiratory system
• Nosepharynxtracheabronchibronchiolesalveoli

7
AP

• Alveoli and pulmonary capillaries separated by
  thin membrane
• Membrane allows gasses to move between blood and
  inspired air
• Oxygen moves from air to blood pass through
  membrane
• Carbon dioxide moves from blood to air through
  membrane

8
AP

• Bronchioles are lined with smooth muscle that
  controls the amount of air entering the lungs.
• Bronchioles can change diameter to meet needs of
  body
• Smooth muscle controlled by autonomic nervous
  system
• 1. In flight or fight response beta 2
  receptors of sympathetic NS is stimulated
• Bronchiolar smooth muscle relaxeslumen widens
• Bronchodilation occurs
• More air enters alveoli
• Increase oxygen to body.

9
AP

• 2. At rest nerves of parasympathetic NS
  stimulated
• Bronchiolar smooth muscle contractslumen narrows
• Bronchoconstriction occurs

10
AP

• Inhalation is a common route of administration
  for pulmonary drugs because it delivers
  medications directly to their site of action.
• The onset of action of inhaled substances is
  almost immediate.

11
AP

• Drugs are often administered by the inhalation
  route for the local effect
• Immediate relief of bronchospasm
• Loosen thick mucus in the bronchial tree
• Drug delivered directly where it is needed.

12
AP

• Devices used for the inhalation route
• 1. Nebulizerssmall machines
• Vaporize a liquid drug into a fine mist to
  inhale.
• Use a facemask
• 2. Dry powder inhaler (DPI)
• Used to inhale powdered solid drug
• Device activated by inhalation
• Types of DPIsturbohaler, rotahaler
• 3. Metered dose inhaler (MDI)
• Use a propellant to deliver a measured dose of
  drug during inhalation
• Client times inhalation to puffs of drug emitted

13
Asthma

• Asthma is a chronic inflammatory disease
  characterized by bronchospasm
• Common chronic condition in US affects 15
  million
• Acute bronchospasm causes dyspnea, coughing,
  gasping for air

14
Asthma

• Acute inflammatory response activated causing
  mucus secretion and edema of airway
• Status asthmaticus
• Severe prolonged form of asthma
• Unresponsive to drug treatment
• May lead to respiratory failure

15
AP

• Goals of drug therapy
• Terminate acute bronchospasms in progress
• Reduce frequency of acute asthma attacks
• Different drugs needed to achieve each goal

16
Beta-Adrenergic Agonists

• Beta-adrenergic agonists are the most effective
  drugs for relieving acute bronchospasm, although
  methylxanthines and anticholinergics are
  alternativesTable 25.2 pg. 475.

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Beta-Adrenergic Agonists

• (sympathomimetics) drugs of choice
• Selective for beta 2 receptors in the lungs
• Fewer cardiac S/E
• When inhaled relax bronchiolar smooth muscle
  producing rapid bronchodilation
• Produce little systemic toxicity

18
Beta-Adrenergic Agonists

• Oral beta-adrenergic agonists
• Longer duration of action
• Frequent side effects tachycardia and tremors

19
Beta-Adrenergic Agonists

• Tolerance may develop to therapeutic effects of
  beta-agonists
• Anticholinergic drugs block parasympathetic
  nervous system
• Cause bronchodilation
• Ipratropium (atrovert, Combivent)
• Most widely used drug in this class
• Inhaled
• Few systemic side effects
• Less effective than beta-agonists

20
Beta-Adrenergic Agonists

• Inhaled anticholinergics not that effective when
  used alone
• Beneficial when used with beta-agonists or
  glucocorticoids
• Methylxanthinesdrug of choice for
  bronchoconstriction twenty years ago
• Theophylline (Theo-dur) and aminophylline
  (Somophylline)
• Chemically related to caffeine.

21
Beta-Adrenergic Agonists

• Theophylline
• Narrow margin of safety
• Interacts with many drugs
• Replaced by safer and more effective drugs
• Side effects common
• N/V, CNS stimulation, dysrhythmias at high doses
• Used primarily for long-term oral prophylaxis of
  persistent asthma

22
Beta-Adrenergic Agonists

• DPsalmeterol (Serevent)beta-adrenergic agonist
  pg. 476
• Not indicated for acute bronchospasm

23
Glucocorticoids

• Glucocorticoids are very effective for the
  long-term prophylaxis of asthmaTable 25.3 pg.
  478.
• Most effective drug available for prevention of
  acute asthmatic episodes
• Suppress inflammation without major side effects
• Inhaled daily to produce therapeutic effects
• Not effective in stopping episodes in progress

24
Glucocorticoids

• Sometimes beta-adrenergic agonist prescribed
  alsoif sodose of glucocorticoids can be reduced
  as much as 50.

25
Glucocorticoids

• Oral glucocorticoids prescribed for severe,
  persistent asthma unresponsive to other treatment
• Take longer than 10 days may produce significant
  adverse effects
• Adrenal gland suppression
• Peptic ulcers
• hyperglycemia

26
Glucocorticoids

• DPbeclomethasone (Beclovent, Beconase,
  Vancenase, Vanceril)aerosol inhalation (asthma),
  nasal spray (allergic rhinitis)
• Not a bronchodilator do not use to stop asthma
  attacks in progress
• Can mask infections

27
Mast Cell Inhibitors

• Cromolyn is one of the safest drugs used for the
  prophylaxis of asthma but it is not effective at
  relieving acute bronchospasm

28
Mast Cell Inhibitors

• Cromolyn (Intal)-anti-inflammatory drug
• Useful in preventing asthma attacks
• Administered by an MDI or a nebulizer
• Safe alternative to glucocorticoids
• Must take daily
• Should not be used to stop acute attacks
• Intranasal form used to treat seasonal allergies

29
Mast Cell Inhibitors

• Nedocromil (Tilade)anti-inflammatory drug
• Similar actions and uses as cromolyn
• Administered with an MDI
• Few adverse effects

30
Mast Cell Inhibitors

• Cromolyn and nedocromilmast-cell stabilizers
• Prevent mast cells from releasing histamine and
  other chemical mediators of inflammation.

31
Antitussives, Expectorants, Mucolytics

• Several drugs are effective at loosening
  bronchial secretions and relieving cough
• Cougha normal reflex to forcibly remove excess
  secretions and foreign material from bronchial
  tree.

32
Antitussives, Expectorants, Mucolytics

• Antitussivescontrol cough
• Used for dry, hacking, non-productive cough
• Irritating to the membranes
• Deprive client of rest
• Not for clients with emphysema and bronchitis
• Do not want to suppress cough

33
Antitussives, Expectorants, Mucolytics

• Narcotic analgesics most effective class of
  antitussives
• Codeine cough mixturesSchedule V drug
• Most frequently used opioid antitussive
• Low doses needed to suppress cough reflex
• Minimal potential for dependence
• For more serious cough conditions

34
Antitussives, Expectorants, Mucolytics

• most frequently used OTC antitussive
• Included in most cold and flu preparations
• Side effects very rare
• no risk of dependence

35
Antitussives, Expectorants, Mucolytics

• Expectorantsdrugs that increase bronchial
  secretions
• Reduce thickness (viscosity) of bronchial
  secretions
• Increasing mucus flow
• Remove more easily by coughing
• most effective OTC expectorant
• Few adverse effects
• Common ingredient in many OTC cold and flu
  preparations
• Higher doses available by prescription

36
Antitussives, Expectorants, Mucolytics

• Mucolyticsdirectly loosen thick, viscous
  bronchial secretions
• Acetylcysteine (Mucomyst)
• Delivered by inhalation
• Available by prescription only
• Used in cystic fibrosis or other diseases that
  produce large amounts of thick bronchial
  secretions.

37
Antitussives, Expectorants, Mucolytics

• COPD are progressive disorders treated with
  multiple pulmonary drugs
• COPD-major cause of death and disability
• Two primary disorders classified as COPDs
• Chronic bronchitis
• Emphysema

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Antitussives, Expectorants, Mucolytics

• Chronic bronchits
• Excessive mucus produced in bronchial tree due to
  inflammation and irritation
• Airways partially obstructed with mucus
• Signsdyspnea and coughing
• Pulmonary infections common
• Exchange of gasses impaired

39
Antitussives, Expectorants, Mucolytics

• Emphysematerminal stage of COPD
• Bronchioles lose elasticity
• Alveoli dilate to maximum size to get more air
  into lungs
• Sign-extreme dyspnea with slightest physical
  activity

40
Antitussives, Expectorants, Mucolytics

• Goals of pharmacologic therapy
• Treat infections
• Control cough
• Control bronchospasm

41
Antitussives, Expectorants, Mucolytics

• Pharmacologic therapies do not cure COPD, only
  treat symptoms
• Drugs used in COPD
• Bronchodilators
• Mucolytics
• expectorants