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

Copyright © 2015 Cengage Learning® 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 2

Copyright © 2015 Cengage Learning® Introduction (cont’d.) Therapeutic measures for respiratory distress –Oxygen therapy –Respiratory stimulants –Bronchodilators –Corticosteroids –Mucolytics and expectorants –Antitussives –Smoking cessation 3

Copyright © 2015 Cengage Learning® Introduction (cont’d.) The following slides discuss various respiratory system drugs and antihistamines –Refer to the chapter for specific side effects, contraindications, and interactions 4

Copyright © 2015 Cengage Learning® 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 5

Copyright © 2015 Cengage Learning® Respiratory Stimulants Caffeine citrate –Treats neonatal apnea of prematurity Theophylline –Administered IV and orally to stimulate respiration in infants (as an alternative to caffeine) 6

Copyright © 2015 Cengage Learning® 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) 7

Copyright © 2015 Cengage Learning® 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 8

Copyright © 2015 Cengage Learning® 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 9

Copyright © 2015 Cengage Learning® 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 10

Copyright © 2015 Cengage Learning® 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 11

Copyright © 2015 Cengage Learning® 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 12

Copyright © 2015 Cengage Learning® 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 13

Copyright © 2015 Cengage Learning® 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 14

Copyright © 2015 Cengage Learning® 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 15

Copyright © 2015 Cengage Learning® Antihistamines Competitively antagonize the histamine 1 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) 16

Copyright © 2015 Cengage Learning® 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) 17

Copyright © 2015 Cengage Learning® 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 18

Copyright © 2015 Cengage Learning® 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 19

Copyright © 2015 Cengage Learning® 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 20