PHARM CH5.pptx
Transcript
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
