Anti-Asthmatics Flashcards

1
Q

Asthma

A

a common disease characterized by airway inflammation and episodic, reversible bronchospasm with severe shortness of breath. Subsets of clinical asthma may reflect differently
pathogenic factors and different responsiveness to currently
available therapies

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2
Q

Drugs useful in classic allergic asthma include (Bronchodilators)

A

Beta agonist
Muscarinic agonist
Methylxanthines

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3
Q

Anti-inflammatory agents

A

inflammatory release inhibitorsSteroids

Slow-antiinflammatory drugs, Antibodies

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4
Q

leukotriene antagonists

A

Lipoxygenase inhibitors, Receptor inhibitors

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5
Q

COPD drugs

A

bronchodilators, Steroids, and antibiotics

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6
Q

Bronchial hyperreactivity

A

Pathologic increase in the bronchoconstrictor response to antigens and irritants; caused by
bronchial inflammation

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7
Q

IgE-mediated disease

A

Disease caused by excessive or misdirected immune response mediated by IgE antibodies.
Example: asthma

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8
Q

Mast cell degranulation

A

Exocytosis of granules (vesicles) from mast cells with a release of mediators of inflammation and bronchoconstriction

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9
Q

Phosphodiesterase (PDE)

A

Family of enzymes that degrade cyclic nucleotides to nucleotides, for example, second messenger
cAMP (active) converted to AMP (inactive) or cGMP to GMP

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10
Q

Tachyphylaxis

A

Rapid loss of responsiveness to a stimulus (eg, a bronchodilator drug)

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11
Q

PATHOPHYSIOLOGY OF ASTHMA (immunologic causes)

A

The immediate cause of asthmatic bronchoconstriction is the release
of several mediators from IgE-sensitized mast cells and other cells
involved in immunologic response

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12
Q

mediators involved in asthma

A

leukotrienes LTC4 and LTD4, tryptase, histamine, and
prostaglandin D2. These substances bring about the “early response”
consisting of bronchoconstriction and increased secretions

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13
Q

“late response” of asthma

A

chemotactic mediators such as LTB4 attract inflammatory cells
to the airways and several cytokines, and some enzymes are released,
resulting in the “late response” leading to inflammation

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14
Q

Chronic inflammation leads to

A

Hyperreactivity y to various inhaled substances, including antigens, histamine, muscarinic agonists, and irritants such as sulfur dioxide (SO2) and cold air. This
reactivity is partially mediated by vagal reflexes

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15
Q

STRATEGIES OF ASTHMA THERAPY

A

Acute bronchospasm must be treated promptly and effectively with bronchodilators (“reliever” drugs). Beta2 agonists, muscarinic antagonists, and theophylline and its derivatives are available for this indication.

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16
Q

How is asthma treated long term

A

The most important anti-inflammatory drugs in the treatment of chronic asthma are corticosteroids. Long-acting β2 agonists can improve the response to corticosteroids. Anti-IgE antibodies also appear promising for chronic therapy. The leukotriene
antagonists

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17
Q

mechanisms of Beta agonist

A

stimulate Adenylyl cyclase, cAMP activity increases- relaxation of bronchial smooth muscle

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18
Q

MOA of Methylxanthines (found in tea, coffee, and cocoa)

A

inhibits Phosphodiesterase activity (degrades cAMP to AMP)- to increase cAMP levels, in turn, cause vasodilation and relaxing bronchial smooth muscle.
Methylxanthines also inhibits adenosine receptors (which leads to constriction)

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19
Q

MOA of Leukotriene antagonist

A

`inhibit LTE4 receptor, prevents exercise-induced asthma and aspirin induced bronchospasm

20
Q

MOA of Musc. antagonists

A

block Ach receptors, preventing bronchoconstriction

21
Q

MOA of corticosteroids

A

reduce the synthesis of PA2 and inhibits COX-2, reduced levels of PGs and Leukotrienes

22
Q

CROMOLYN & NEDOCROMIL

A

Cromolyn (disodium cromoglycate) and nedocromil are unusually insoluble chemicals; so even massive doses given orally or by the aerosol result in minimal systemic blood levels.

23
Q

MOA of Cromolyn and Nedocromil

A

The mechanism of action of these drugs is poorly understood
but may involve a decrease in the release of mediators (such as
leukotrienes and histamine) from mast cells. The drugs have
no bronchodilator action but can prevent bronchoconstriction
caused by a challenge with antigen to which the patient is allergic.
Cromolyn and nedocromil are capable of preventing both early
and late responses to challenge

24
Q

ANTI-IgE ANTIBODIES

A

Omalizumab is a humanized murine monoclonal antibody to
human IgE. It binds to the IgE on sensitized mast cells and prevents activation by asthma trigger antigens and subsequent release
of inflammatory mediators. Although approved in 2003 for the
prophylactic management of severe asthma, experience with this
drug is limited because it is very expensive and must be administered parenterally

25
benralizumab, mepolizumab, and reslizumab antibodies that target
IL-5
26
dupilumab, which targets the | receptor for
IL4-alpha and IL-13
27
Methylxanthines Clinical app
Asthma, especially prophylaxis against nocturnal attacks
28
Pharmacokinetics of Methylxanthines
Oral slow-release Duration: 12 h Aminophylline, salt for IV use
29
Toxicities, Interactions of Methylxanthine
Insomnia, tremor, anorexia, seizures, arrhythmias
30
Roflumilast
a nonpurine molecule with effects similar to theophylline but more selective for PDE4; approved for COPD
31
Caffeine
similar to theophylline with increased CNS effect, not used in asthma or COPD
32
Theobromine:
similar to theophylline not used in asthma or COP
33
Antimuscarinic agents
Ipratropium, tiotropium, aclidinium Competitive pharmacologic muscarinic antagonists Asthma and chronic obstructive pulmonary disease Inhalation (aerosol) Duration: several hours Dry mouth, cough
34
prototype drugs (Cromolyn and nedocromil)
Reduce release of inflammatory and bronchoconstrictor mediators from sensitized mast cells Rarely used prophylaxis of asthma; cromolyn also used for ophthalmic, nasopharyngeal, and gastrointestinal allergy Inhaled aerosol for asthma • cromolyn local application for other applications Duration: 3–6 h Cough when used by inhalation
35
Leukotriene antagonists (Montelukast, zafirlukast)
Pharmacologic antagonists at LTD4 receptors Prophylaxis of asthma Oral Duration: 12–24 h Minimal side-effects
36
Zileuton
Inhibitor of lipoxygenase • reduces synthesis of leukotrienes Prophylaxis of asthma Oral Duration: 12 h Elevation of liver enzymes
37
Corticosteroids | Inhaled (Beclomethasone)
Inhibition of phospholipase A2 • reduces expression of cyclooxygenase Prophylaxis of asthma: drugs of choice Inhalation Duration: 10–12 h Pharyngeal candidiasis; minimal systemic steroid toxicity (eg, adrenal suppression)
38
Systemic Corticosteroids (Prednisone)
Like inhaled corticosteroids Treatment of severe refractory chronic asthma Oral; Duration: 12–24 h Adrenal suppression, growth inhibition, muscle wasting, osteoporosis, salt retention, glucose intolerance, behavioral changes
39
Antibody (Omalizumab)
``` Binds IgE antibodies on mast cells; reduces the reaction to inhaled antigen Prophylaxis of severe, refractory asthma not responsive to all other drugs Parenteral • administered as several courses of injections Extremely expensive • long-term toxicity not yet well documented ```
40
Short-acting beta agonists
``` Albuterol Beta2-selective agonist -bronchodilation Asthma acute attack relief drug of choice (not for prophylaxis) Inhalation (aerosol) Duration: 2–4 h Tremor, tachycardia ```
41
Metaproterenol, terbutaline
similar to albuterol; terbutaline also available as oral and parenteral formulations
42
Long-acting beta agonists
Salmeterol, formoterol, indacaterol, vilanterol Beta2-selective agonists; bronchodilation; potentiation of corticosteroid action ``` Asthma prophylaxis (not for acute relief) • indacaterol and vilanterol for COPD ``` Inhalation (aerosol) Duration: 12–24 h Tremor, tachycardia, cardiovascular events
43
Nonselective sympathomimetics
Epinephrine, isoproterenol Nonselective β activation-epinephrine also an α agonist Asthma (obsolete) Inhalation (aerosol, nebulizer) Duration: 1–2 h Nausea, Dizziness, Pale skin, Tachycardia
44
Indirect-acting sympathomimetic
``` Ephedrine Releases stored catecholamines- causes nonselective sympathetic effects Asthma (obsolete) Oral Duration: 6–8 h ``` Insomnia, tremor, anorexia, arrhythmias
45
Roflumilast
a nonpurine molecule with effects similar to theophylline but more selective for PDE4; approved for COPD
46
Caffeine
similar to theophylline with increased CNS effect, not used in asthma or COPD
47
Theobromine
similar to theophylline not used in asthma or COPD