Drugs Acting on the Respiratory System PDF

Drugs Acting on the Respiratory System NCM 106 Pharmacology Anatomy of Respiratory System Respiratory Membrane  Antitussives Antitussives are drugs that suppress the cough reflex. Many disorders of the respiratory tract, including the common cold, sinusitis, pharyngitis, an...

Drugs Acting on the Respiratory System NCM 106 Pharmacology Anatomy of Respiratory System Respiratory Membrane  Antitussives Antitussives are drugs that suppress the cough reflex. Many disorders of the respiratory tract, including the common cold, sinusitis, pharyngitis, and pneumonia, are accompanied by an uncomfortable, unproductive cough. The traditional antitussives include codeine (generic), hydrocodone (available in some combination products), and dextromethorphan (generic and in combination products), which act directly on the medullary cough center of the brain to depress the cough reflex. B  Antitussives Other antitussives have a direct effect on the respiratory tract. Benzonatate (Tessalon) acts as a local anesthetic on the respiratory passages, lungs, and pleurae, blocking the effectiveness of the stretch receptors that stimulate a cough reflex. All of these drugs are indicated for treatment of a nonproductive cough. Adverse Effects Antitussive drugs should be used with caution in any situation in which coughing could be important for clearing the airways.  Decongestants cause local vasoconstriction, thereby reducing blood flow to the mucous membranes of the nasal passages and sinus cavities. Rebound vasodilation (rhinitis medicamentosa) is an adverse effect of excessive or long-term decongestant use.  Topical nasal decongestants are preferred for patients who need to avoid the systemic adrenergic effects associated with oral decongestant Topical nasal steroid decongestants block the inflammatory response and are preferred for patients with allergic rhinitis for whom systemic steroid therapy is undesirable.  Antihistamines Patients taking antihistamines may react to dryness of the skin block the release or action and mucous membranes. The of histamine, a chemical nurse should encourage them to released during drink plenty of fluids, use a inflammation that increases humidifier if possible, avoid secretions and narrows smoke-filled rooms, and use good skin care and moisturizers. airways Antihistamines should be avoided with any patient who has a prolonged QT interval because serious cardiac complications and even death have occurred.  Expectorants Expectorants are drugs Guaifenesin is the that liquefy the lower only expectorant respiratory tract currently available. secretions. They are Care should be taken used for the to avoid inadvertent symptomatic relief of overdose when using respiratory conditions OTC products that characterized by a dry, might contain this nonproductive cough. drug.  Mucolytics Mucolytics work to Dornase alfa is break down mucus to specific for the aid high-risk treatment of patients respiratory patients in with cystic fibrosis, coughing up thick, which is characterized tenacious secretions. by a thick, tenacious mucus production that can block airways.  Drugs Acting on the Lower Respiratory Tract Bronchodilators (antiasthmatics) facilitate respiration by Steroids are used to dilating the airways decrease the inflammatory response in Bronchodilators include the airway. Inhaling the steroid tends to decrease xanthines, the numerous systemic sympathomimetics, and effects that are anticholinergics associated with steroid use.  Drugs Acting on the Lower Respiratory Tract Leukotriene receptor Lung surfactants are antagonists block or instilled into the antagonize receptors respiratory system of for the production of premature infants leukotrienes D4 and who do not have E4, thus blocking enough surfactant to many of the signs and ensure alveolar symptoms of asthma. expansion.