Narrated Asthma (Ch

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Pharm Ch. 75

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Chapter 75: 

Chapter 75 Drugs for Asthma

Asthma: 

Asthma Chronic inflammatory disorder of the airway Characteristic signs and symptoms: Sense of breathlessness Tightening of the chest Wheezing Dyspnea Cough Cause: immune-mediated airway inflammation

Pathophysiology: 

Pathophysiology See Figure 75-1 Symptoms of asthma result from a combination of inflammation and bronchoconstriction, so treatment must address both components.

PowerPoint Presentation: 

Fig. 75-1. Allergen-induced inflammation and bronchospasm in asthma.

Overview of Drugs for Asthma: 

Overview of Drugs for Asthma Two main pharmacologic classes: Anti-inflammatory agents Glucocorticoids (prednisone) Bronchodilators Beta 2 agonists (albuterol)

Inhalation Drug Therapy: 

Inhalation Drug Therapy Three obvious advantages: Therapeutic effects are enhanced Systemic effects are minimized Relief of acute attacks is rapid Three types: Metered-dose inhalers (MDIs) Dry-powder inhalers (DPIs) Nebulizers

PowerPoint Presentation: 

Fig. 75-2. Impact of a spacer device on the distribution of inhaled medication. Note that, when a spacer is used, more medication reaches its site of action in the lungs, and less is deposited in the mouth and throat.

Anti-Inflammatory Drugs: 

Anti-Inflammatory Drugs Foundation of asthma therapy Taken daily for long-term control Principal anti-inflammatory drugs are the glucocorticoids

Anti-Inflammatory Drugs – Glucocorticoids: 

Anti-Inflammatory Drugs – Glucocorticoids Include budesonide and fluticasone Considered the most effective antiasthma drugs available Usually administered by inhalation, but IV and oral are also options

Anti-Inflammatory Drugs – Glucocorticoids: 

Anti-Inflammatory Drugs – Glucocorticoids Mechanism of action = suppress inflammation Decreased synthesis and release of inflammatory mediators Decreased infiltration and activity of inflammatory cells Decreased edema of the airway mucosa

Anti-Inflammatory Drugs – Glucocorticoids: 

Anti-Inflammatory Drugs – Glucocorticoids Adverse effects: Minor when taken acutely Can be severe when used long-term (adrenal suppression, osteoporosis, hyperglycemia, and others)

Anti-Inflammatory Drugs – Leukotriene Modifiers: 

Anti-Inflammatory Drugs – Leukotriene Modifiers Suppress effects of leukotrienes Less effective than inhaled glucocorticoids Available agents: Zileuton (Zyflo) Zafirlukast (Accolate) Montelukast (Singulair)

Anti-Inflammatory Drugs – Cromolyn: 

Anti-Inflammatory Drugs – Cromolyn Used for prophylaxis, not quick relief Suppresses inflammation; not a bronchodilator Route – inhalation: Nebulizer MDI Adverse effects Safest of all antiasthma medications Cough Bronchospasm

Bronchodilators: 

Bronchodilators Provide symptomatic relief but do not alter the underlying disease process (inflammation) In almost all cases, patient taking a bronchodilator should also be taking a glucocorticoid for long-term suppression of inflammation Principal bronchodilators are the beta 2 -adrenergic agonists

Bronchodilators – Beta2-Adrenergic Agonists: 

Bronchodilators – Beta 2 -Adrenergic Agonists Include albuterol, salmeterol, terbutaline Most effective drugs for relief of acute bronchospasm and prevention of exercise-induced bronchospasm Use in asthma: both quick relief and long-term control

Bronchodilators – Beta2-Adrenergic Agonists: 

Bronchodilators – Beta 2 -Adrenergic Agonists Adverse effects Inhaled preparations Systemic effects – tachycardia, angina, and tremor Oral preparations Excessive dosage – angina pectoris, tachydysrhythmias Tremor

Bronchodilators – Beta2-Adrenergic Agonists: 

Bronchodilators – Beta 2 -Adrenergic Agonists Mechanism of action Activate beta 2 receptors in smooth muscle of lung, promoting bronchodilation and thereby relieving bronchospasm Also suppress histamine release in lung and increase ciliary motility

Bronchodilators – Methylxanthines: 

Bronchodilators – Methylxanthines Theophylline Benefits derive primarily from bronchodilation Narrow therapeutic index Plasma level 10 to 20 mcg/mL Toxicity is related to theophylline levels Other methylxanthines include aminophylline and dyphylline

Glucocorticoid/LABA Combinations: 

Glucocorticoid/LABA Combinations Available combinations Fluticasone/salmeterol (Advair) Budesonide/formoterol (Symbicort) Indicated for long-term maintenance in adults and children Not recommended for initial therapy

Chronic Asthma Management: 

Chronic Asthma Management Tests of lung function Forced expiratory volume in 1 second (FEV 1 ) Forced vital capacity (FVC) Peak expiratory flow (PEF)

Chronic Asthma Management: 

Chronic Asthma Management Four classes of chronic asthma Intermittent Mild persistent Moderate persistent Severe persistent

Chronic Asthma Management: 

Chronic Asthma Management Treatment goals Reducing impairment Reducing risk

Chronic Asthma Management: 

Chronic Asthma Management Chronic drug therapy Agents for long-term control (eg, inhaled glucocorticoids) Agents for quick relief of ongoing attack (eg, inhaled SABAs)

Chronic Asthma Management: 

Chronic Asthma Management Stepwise therapy Step chosen for initial therapy is based on pretreatment classification of asthma severity Moving up or down a step is based on ongoing assessment of asthma control

Chronic Asthma Management: 

Chronic Asthma Management Important to reduce exposure to allergens and triggers Sources of allergens: house dust mites, pets, cockroaches, mold Factors that can exacerbate asthma: tobacco smoke, wood smoke, household sprays