Copyright © 2015 Cengage Learning® Chapter 26 Respiratory System Drugs and Antihistamines

Copyright © 2015 Cengage Learning®

Chapter 26Respiratory System Drugs and

Antihistamines


Introduction• Respiratory diseases and disorders

– According to the American Lung Association, lung disease is the third leading cause of death in the U.S.

– Respiratory diseases range from mild and self-limiting such as the common cold, to life-threatening such as bacterial pneumonia, pulmonary embolism, and lung cancer

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Introduction (cont’d.)• Therapeutic measures for respiratory

distress – Oxygen therapy– Respiratory stimulants– Bronchodilators– Corticosteroids– Mucolytics and expectorants– Antitussives– Smoking cessation

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Introduction (cont’d.)• The following slides discuss various

respiratory system drugs and antihistamines– Refer to the chapter for specific side effects,

contraindications, and interactions

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Oxygen• Oxygen treatment

– Used therapeutically for hypoxia (insufficient oxygen supply to the tissues)

– Decreases the workload of the heart and respiratory system (especially during distress)

– Treats heart and lung diseases and some central nervous system (CNS) conditions with respiratory difficulty or failure

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Respiratory Stimulants• Caffeine citrate

– Treats neonatal apnea of prematurity • Theophylline

– Administered IV and orally to stimulate respiration in infants (as an alternative to caffeine)

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Bronchodilators• Act by relaxing smooth muscles of the

bronchial tree, relieving bronchospasm and decreasing the work of breathing– For symptomatic treatment of acute

respiratory conditions such as asthma and some forms of COPD

– Can be given orally, parenterally, and by inhalation• Metered dose inhalers (MDIs), dry-powder inhalers

(DPIs), and small volume nebulizers (SVNs)

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Bronchodilators (cont’d.)• Sympathomimetics (adrenergics)

– Potent bronchodilators that increase vital capacity and decrease airway resistance

– Examples: albuterol, epinephrine, salmeterol, and others

• Anticholinergics (parasympatholytics)– Decrease the chemical that promotes

bronchospasm– Example: Atrovent

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Bronchodilators (cont’d.)• Xanthines

– Relaxes the smooth muscle of the bronchial airways and pulmonary blood vessels

– May possess anti-inflammatory actions– No longer a first-line treatment

• Modest clinical effectiveness• Need for serum monitoring• Many adverse effects and drug interactions

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Corticosteroids• Synthetic corticosteroids

– Relieve inflammation, reduce swelling, decrease bronchial hyper-responsiveness to triggers, and suppress symptoms in acute and chronic reactive airway disease

– Administered systemically for short-term “bursts” during exacerbations, and occasionally at the beginning of treatment until symptoms are controlled

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Corticosteroids (cont’d.)• Inhaled corticosteroids (SVN aerosol, DPI,

MDI)– Preferred drug therapy in long-term

prophylactic management of persistent asthma of various severities

• Intranasal corticosteroids– Increasingly considered first-line therapy for

most noninfectious types of rhinitis– Reduce congestion, edema, and inflammation

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Asthma Prophylaxis• Leukotriene inhibitors

– Zafirlukast (Accolate) and montelukast (Singulair) • Oral leukotriene receptor antagonists for asthma

prophylaxis, prevention of exercise-induced bronchoconstriction, and treatment of chronic asthma

• Help control inflammatory process of asthma caused by leukotriene production, thus helping to prevent asthma symptoms and acute attacks

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Asthma Prophylaxis (cont’d.)• Mast cell stabilizers

– Rupture or degranulation of mast cells and subsequent spilling of their chemical mediator contents cause an inflammatory response that can lead to asthma

– Stabilizing the mast cell membrane has anti-inflammatory actions that modify the release of mediators from mast cells and eosinophils

– Example: cromolyn

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Mucolytics and Expectorants• Mucolytics

– Decrease hypersecretion and increase thinning of pulmonary secretions

– Example: acetylcysteine• Expectorants

– Increase secretions, reduce viscosity, and help to expel sputum

– Example: guaifenesin

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Antitussives• Prevent coughing in patients not requiring

a productive cough– Most produce cough suppression by acting

centrally on the cough center located in the brainstem

– Narcotic antitussive example: codeine – Nonnarcotic antitussive example:

dextromethorphan

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Antihistamines• Competitively antagonize the histamine1

receptor sites– Combat the increased capillary permeability

and edema, inflammation, and itch caused by sudden histamine release• To treat allergy symptoms

– First generation: diphenhydramine (Benadryl)– Second-generation: fexofenadine (Allegra)

and loratadine (Claritin)

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Decongestants• Constrict blood vessels in the respiratory

tract– Results in shrinkage of swollen mucous

membranes and helps to open nasal airway passages

– Frequently combined with antihistamines, analgesics, caffeine, and/or antitussives

– Examples: phenylephrine (Neo-Synephrine) or pseudoephedrine (Sudafed)

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Safety of Cough/Cold/Allergy Products

• Many cough and cold formulations combine several drugs– Use only if the corresponding symptom is

present and each individual component is available in the proper strength and dosing interval a patient may need

– Caution patients to seek advice from a healthcare professional familiar with each ingredient

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Smoking Cessation Aids• Nicotine replacement therapy

– Help lessen withdrawal symptoms by slowly lowering the level of nicotine in the body

– Examples: Nicorette gum, Commit lozenges, Nicoderm CQ patch, and Nicotrol inhaler and nasal spray

• Buproprion– Oral antidepressant drug (Wellbutrin) – Associated with decreases in cravings and

lessening of nicotine withdrawal

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Smoking Cessation Aids (cont’d.)• Varenicline (Chantix)

– Partial nicotine receptor agonist-antagonist– Alleviates symptoms of nicotine craving and

withdrawal through agonist activity while inhibiting the effects of repeated nicotine exposure by its antagonist activity

– Eliminates the pleasurable feelings associated with smoking

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Copyright © 2015 Cengage Learning® Chapter 26 Respiratory System Drugs and Antihistamines