PHARM CH5.pptx

Chapter 5 D R U G S U S E D I N R E S P I R AT O RY S Y S T E M DISORDERS Introduction Disease Processes Defense Mechanisms Respiratory Anatomy and Physiology Upper respiratory system  Nostrils, nasal cavity, pharynx, larynx, trachea & bronchi Lower respiratory system  Bronchioles & alveo...

Chapter 5 D R U G S U S E D I N R E S P I R AT O RY S Y S T E M DISORDERS Introduction Disease Processes Defense Mechanisms Respiratory Anatomy and Physiology Upper respiratory system  Nostrils, nasal cavity, pharynx, larynx, trachea & bronchi Lower respiratory system  Bronchioles & alveoli Functions     O2-CO2 exchange Regulation of acid-base balance Body temp. regulation Voice production Respiratory Anatomy and Physiology Division of work  Ventilation  Distribution  Diffusion  Perfusion Respiratory Defense Mechanisms Nasal cavity  Turbinates  Hair Protective reflexes     Cough Sneeze Reverse sneeze Laryngospasm & bronchospasm Mucociliary clearance  Mucus, cilia, macrophages, IgA Principles of Respiratory Therapeutics Importance of correct diagnosis 3 general goals of tx  Control of secretions    Control of reflexes     Remove the cause Make less viscid Antitussives & bronchodilators Removal of offending agent & vasoconstrictors Bronchodilators & corticosteriods Maintaining normal airflow to the alveoli    Bronchodilators Diuretics & mucolytics O2 therapy Inhalation Therapy Aerosolization (nebulation) – allows delivery of drugs at high concentrations directly to the airways with minimum increase in blood levels Efficacy variables   Dose Distribution Distribution factors  Size, shape & pattern of airway  Breathing pattern of animal  Size of inhaled particle  Airway pathology Categories of Respiratory Drugs Expectorants Mucolytics Antitussives Bronchodilators Decongestants Antihistamines Corticosteriods Miscellaneous Expectorants Oral (inhalation or parenterally) +/- antihistamine or dextromethorphan Guaifenesin    Uses – cough symptoms due to URT conditions Dosage forms – liquid & tablet Adverse side effects – mild drowsiness or nausea Mucolytics Nebulized Oral form available for acetaminophen toxicity Acetylcysteine   Uses – break down thick or inspissated respiratory mucus Adverse side effects – nausea or vomiting (oral admin.) Antitussives Centrally or peripherally acting Butorphanol tartrate  Uses – chronic, nonproductive cough  Dosage forms – injectable & tablets  Adverse side effects – sedation & ataxia Hydrocodone bitartrate  Uses – harsh, nonproductive coughs  Dosage forms – syrup & tablets  Adverse side effects – sedation, constipation & GI upset Antitussives Codeine     Opiate agonist, class V controlled drug Uses – harsh, nonproductive cough Dosage forms – syrups Adverse side effects – sedation & constipation Dextromethophan     Nonnarcotic, no analgesic or addictive properties Uses – suppress nonproductive cough Dosage forms – syrups Adverse side effects – drowsiness & GI upset (rare) Antitussives Temaril-P     Contains an antitussive (trimeprazine tartrate) & a corticosteroid (prednisolone) Uses – antitussive & antipruritic Dosage forms – tablets Adverse side effects – sedation, depression, hypotension, minor CNS signs Bronchodilators Bronchoconstriction results from  Release of Ach at PS n. endings or inhibition of its breakdown  Release of histamine  Blockade of beta-2-adrenergic receptors 4 main categories of bronchodilators  Cholinergic blockers  Antihistamines  Beta-2-adrenergic agonists  Methylxanthines Bronchodilators Cholinergic blockers  Combine w/ Ach receptors on smooth m. & block Ach  Atropine, aminopentamide & glycopyrrolate  Used in cases of organophosphate or carbamate (insecticide) toxicity Antihistamines  Discussed later Bronchodilators Beta-2-adrenergic agonists  Dosage forms – epinephrine, isoproterenol, albuterol, salmeterol  Adverse side effects – tachycardia & hypertension Methylxanthines   Dosage forms – aminophylline & theophylline Adverse side effects – GI upset, CNS stimulation, tachycardia, ataxia & arrhythmia Decongestants Dosage forms – spray, nose drops, liquid or tablet Limited use in vet medicine Antihistamines Prevent mast cell degranulation & block H1 receptors on smooth muscle Most effective when used preventatively End in “-amine” Uses – heaves in horses, pneumonia in cattle, feline asthma & insect bites Dosage forms – oral & injectable Adverse side effects – sedation & GI effects (rare) Corticosteroids Uses – tx of heaves in horses, feline asthma, ARDS & allergic pneumonia End in –lone & -sone Dosage forms – inhaled, injectable & oral Adverse side effects – few if used according to recommendations Miscellaneous Respiratory Drugs Antimicrobials (antibiotics) Mast cell stabilizers Diuretics Respiratory stimulants  Doxapram hydrochloride - CNS stimulant      Uses – speed awakening & restore reflexes following anesthesia, neonates following dystocia or C-section Dosage forms – injectable Adverse side effects – hypertension, arrhythmias, hyperventilation, CNS excitation & seizures Naloxone – used for narcotic overdoses Yobine – used for xylazine overdose