Respiratory

• Common respiratory diseases include: Asthma, chronic obstructive pulmonary disease (COPD), and allergic rhinitis
• Coughing is an important defensive respiratory response to irritants
• Cough may represent several etiologies such as the common cold, sinusitis, and/or underlying chronic respiratory disease
• Antitussives are agents that relieve or prevent coughing and are used to reduce respiratory irritation
• Codeine is the most useful narcotic antitussive agent and aids in relieving the pain associated with a cough
• Hydroxylation polymorphisms in CYP2D6 explain an increased susceptibility to several adverse drug reactions related to codeine
• Dextromethorphan is a non-opioid antitussive that is free of analgesic and addictive properties
• Expectorants facilitate the removal of secretions of the bronchopulmonary mucous membrane
• Mucolytics dissolve mucus in the respiratory tract and are used in the treatment of respiratory disorders with purulent, viscid, or excessive secretions
• Bronchodilators cause expansion of the air passages of the lungs and are used in the treatment of asthma and COPD
• Bronchodilator agents (Sympathomimetics) relax the smooth muscle of the bronchioles and include drugs like Albuterol, Salmeterol, Epinephrine, Metaproterenol, Ephedrine, and Isoproterenol
• Bronchodilator agents (Xanthine derivatives) directly relax the smooth muscle of the bronchi and pulmonary blood vessels and include drugs like Aminophylline and Theophylline
• Muscarinic receptor antagonists block contraction of airway smooth muscle and reduce secretion of mucus, with examples like Ipratropium bromide
• Anti-inflammatory agents like corticosteroids are used for the treatment and prophylactic purpose in asthma, and they inhibit the production of inflammatory mediators
• Miscellaneous respiratory agents include Cromolyn and Nedocromil, which work by inhibiting the release of histamine from mast cells
• Leukotriene modifiers like Zafirlukast and Montelukast have been developed for asthma treatment
• Treatment of status asthmaticus includes administration of oxygen, frequent administration of aerosolized β2-agonists, systemic corticosteroids, IV fluids, and antibiotics if needed
• Inhaled albuterol/salbutamol is the most appropriate drug to rapidly reverse bronchoconstriction in a severe asthma attack, while intravenous metoprolol is contraindicated
• Inhaled glucocorticoids should have high oral bioavailability to be useful
• NIH guidelines recommend the institution of routine inhaled corticosteroids for patients classified as having greater than or equal to moderate persistent asthma