The Respiratory System PDF

The Respiratory System Jomark P. Guevara BSN, PhRN, USRN Drugs for Allergic Rhinitis and the Common Cold Physiology of the Upper Respiratory Tract ALLERGIC RHINITIS  or hay fever, is inflammation of the nasal mucosa due to exposure to allergens. Although not life threaten...

The Respiratory System Jomark P. Guevara BSN, PhRN, USRN Drugs for Allergic Rhinitis and the Common Cold Physiology of the Upper Respiratory Tract ALLERGIC RHINITIS  or hay fever, is inflammation of the nasal mucosa due to exposure to allergens. Although not life threatening, allergic rhinitis is a condition affecting millions of patients, and pharmacotherapy is frequently necessary to control symptoms and to prevent secondary complications. The therapeutic goals of treating allergic rhinitis  To prevent its occurrence and to relieve symptoms.  Drugs used to treat allergic rhinitis may be grouped into two simple categories:  Preventers are used for prophylaxis and include antihistamines, intranasal corticosteroids, and mast cell stabilizers.  Relievers are used to provide immediate, though temporary, relief for acute allergy symptoms once they have occurred. Relievers include the oral and intranasal decongestants, usually drugs from the sympathomimetic class. H1-Receptor Antagonists/Antihistamines and Mast  Cell Stabilizers Antihistamines - block the actions of histamine at the H1 receptor. They are widely used as over-the-counter (OTC) remedies for relief of allergy symptoms, motion sickness, and insomnia.  In addition to allergic rhinitis, antihistamines have been used to treat a number of other disorders, including the following:  Vertigo and motion sickness. Nausea resulting from vertigo or motion sickness responds well to antihistamines. These drugs act by suppressing the vomiting center in the medulla and depressing neurons of the vestibular apparatus of the inner ear. To be effective, they must be taken prior to the onset of symptoms. Meclizine (Antivert) and dimenhydrinate (Dramamine) are two common antihistamines used for this purpose. In addition to allergic rhinitis, antihistamines have been used to treat a number of other disorders, including the following: Cont.  Parkinson’s disease. Drugs with significant anticholinergic actions are used to treat mild forms of Parkinson’s disease. They are also used to treat the tremor and certain other adverse effects of conventional antipsychotic drugs. Because diphenhydramine exhibits greater anticholinergic action, it is sometimes used to treat these conditions.  Insomnia. Many patients become drowsy after taking first-generation antihistamines. OTC sleep aids usually include antihistamines such as diphenhydramine and doxylamine (Unisom Sleep Tabs).  Urticaria and other skin rashes. Urticaria, or hives, is often caused by the release of histamine; thus, the condition responds well to H1- receptor antagonists. Symptomatic treatment may include any of the first or second-generation drugs, either using oral drugs or topical creams or lotions. Intranasal Corticosteroids  Corticosteroids, also known as glucocorticoids, are applied directly to the nasal mucosa to prevent symptoms of allergic rhinitis. They have largely replaced antihistamines as preferred drugs for the treatment of perennial allergic rhinitis.  The importance of the corticosteroids in treating severe inflammation. Decongestants  Decongestants are drugs that relieve nasal congestion. They are administered by either the oral or intranasal routes and are often combined with antihistamines in the pharmacotherapy of allergies or the common cold. Acethylcholine Reversal of effect COMMON COLD Antitussives  Antitussives are drugs used to dampen the cough reflex. They are of value in treating coughs due to allergies or the common cold. Expectorants and Mucolytics  Several drugs are available to control excess mucus production. Expectorants increase bronchial secretions, and mucolytics help loosen thick bronchial secretions. Drugs for Asthma and Other Pulmonary Disorders THE LOWER RESPIRATORY SYSTEM Administration of Pulmonary Drugs Via Inhalation  An aerosol is a suspension of minute liquid droplets or fine solid particles suspended in a gas.  A nebulizer is a small machine that vaporizes a liquid medication into a fine mist that is inhaled, using a face mask or handheld device.  If the drug is a solid, it may be administered using a dry powder inhaler (DPI). A DPI is a small device that is activated by the process of inhalation to deliver a fine powder directly to the bronchial tree.  A metered-dose inhaler (MDI) is a third type of device commonly used to deliver respiratory drugs. MDIs use a propellant to deliver a measured dose of drugs to the lungs during each breath. ASTHMA  is a chronic pulmonary disease with inflammatory and bronchospasm components. Drugs may be given to decrease the frequency of asthmatic attacks or to terminate attacks in progress. Common Triggers of Asthma The National Asthma Education and Prevention Program (NAEPP) categorizes asthma drugs into the following two simple classes  Quick-relief medications. Short and intermediate-acting beta2- adrenergic agonists, anticholinergics and systemic corticosteroids.  Long-acting medications. Inhaled corticosteroids, mast cell stabilizers, leukotriene modifiers, long-acting beta2-adrenergic agonists, methylxanthines, and immunomodulators Overview of Drug Classes for Asthma Management BRONCHODIALATORS FOR TREATING ASTHMA  Beta-Adrenergic Agonists  are effective bronchodilators for the management of asthma and other pulmonary diseases.  Beta-adrenergic agonists are drugs that activate the sympathetic nervous system, which relaxes bronchial smooth muscle resulting in bronchodilation.  Anticholinergics  Although beta agonists are drugs of choice for treating acute asthma, anticholinergics are alternative bronchodilators. Only three anticholinergics are used for pulmonary disease  Methylxanthines  The methylxanthines were considered drugs of choice for treating asthma 30 years ago. Now they are primarily reserved for the long-term management of persistent asthma that is unresponsive to beta agonists or inhaled corticosteroids Prophylaxis of Asthma with Corticosteroids  Corticosteroids, also known as glucocorticoids, are the most potent natural anti-inflammatory substances known.  Inhaled corticosteroids are absorbed into the circulation so slowly that systemic adverse effects are rarely observed. Local side effects include hoarseness and oropharyngeal candidiasis  Leukotriene Modifiers are relatively new drugs used to reduce inflammation and ease bronchoconstriction.  are used as alternative drugs in the management of asthma symptoms.  Mast Cell Stabilizers serve limited, though important, roles in the prophylaxis of asthma  These drugs act by inhibiting the release of histamine from mast cells CHRONIC OBSTRUCTIVE PULMONARY DISEASE  Chronic obstructive pulmonary disease (COPD) is a progressive pulmonary disorder characterized by chronic and recurrent obstruction of airflow. The two most common examples of conditions causing chronic pulmonary obstruction are chronic bronchitis and emphysema.  In chronic bronchitis, excess mucus is produced in the lower respiratory tract due to the inflammation and irritation from cigarette smoke or pollutants. The airway becomes partially obstructed with mucus, thus resulting in the classic signs of dyspnea and coughing. An early sign of bronchitis is often a productive cough on awakening.  COPD is progressive, with the terminal stage being emphysema. After years of chronic inflammation, the bronchioles lose their elasticity, and the alveoli dilate to maximum size to allow more air into the lungs. The patient suffers extreme dyspnea from even the slightest physical activity. Pharmacotherapy of COPD  The goals of pharmacotherapy of COPD are to relieve symptoms and avoid complications of the condition.  Most patients receive bronchodilators such as ipratropium (Atrovent), beta2 agonists, or inhaled corticosteroids. Both short-acting and long-acting bronchodilators are prescribed.  Mucolytics and expectorants are sometimes used to reduce the viscosity of the bronchial mucus and to aid in its removal.  Long-term oxygen therapy assists breathing and has been shown to decrease mortality in patients with advanced COPD.  Antibiotics may be prescribed for patients who experience multiple bouts of pulmonary infections.  One of the newer treatments for severe COPD is roflumilast (Daliresp), a drug approved in 2011 that exhibits anti-inflammatory effects on the airways  Patients with COPD should not receive drugs that have beta-adrenergic antagonist activity or otherwise cause bronhoconstriction. Respiratory depressants such as opioids and barbiturates should be avoided. END