Transcript Chapter 26
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 lifethreatening such as bacterial pneumonia, pulmonary embolism, and lung cancer Copyright © 2015 Cengage Learning® 2 Introduction (cont’d.) • Therapeutic measures for respiratory distress – Oxygen therapy – Respiratory stimulants – Bronchodilators – Corticosteroids – Mucolytics and expectorants – Antitussives – Smoking cessation Copyright © 2015 Cengage Learning® 3 Introduction (cont’d.) • The following slides discuss various respiratory system drugs and antihistamines – Refer to the chapter for specific side effects, contraindications, and interactions Copyright © 2015 Cengage Learning® 4 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 Copyright © 2015 Cengage Learning® 5 Respiratory Stimulants • Caffeine citrate – Treats neonatal apnea of prematurity • Theophylline – Administered IV and orally to stimulate respiration in infants (as an alternative to caffeine) Copyright © 2015 Cengage Learning® 6 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) Copyright © 2015 Cengage Learning® 7 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 Copyright © 2015 Cengage Learning® 8 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 Copyright © 2015 Cengage Learning® 9 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 Copyright © 2015 Cengage Learning® 10 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 Copyright © 2015 Cengage Learning® 11 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 Copyright © 2015 Cengage Learning® 12 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 antiinflammatory actions that modify the release of mediators from mast cells and eosinophils – Example: cromolyn Copyright © 2015 Cengage Learning® 13 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 Copyright © 2015 Cengage Learning® 14 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 Copyright © 2015 Cengage Learning® 15 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) Copyright © 2015 Cengage Learning® 16 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) Copyright © 2015 Cengage Learning® 17 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 Copyright © 2015 Cengage Learning® 18 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 Copyright © 2015 Cengage Learning® 19 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 Copyright © 2015 Cengage Learning® 20