Drugs Affecting the Respiratory System PDF

Drugs Affecting the Respiratory System Dr Mashael Al-Mutairi MLS [email protected] Antitussives (cough suppressants)  Cough Removal of respiratory secretions and foreign objects  Two Basic Types of Cough  Productive cough  removes excessive secretions  Nonproductive cough  dry cough ...

Drugs Affecting the Respiratory System Dr Mashael Al-Mutairi MLS [email protected] Antitussives (cough suppressants)  Cough Removal of respiratory secretions and foreign objects  Two Basic Types of Cough  Productive cough  removes excessive secretions  Nonproductive cough  dry cough  after hernia repair surgery  Most antitussive drugs produce cough suppression by acting centrally on the cough center located in the brainstem.  Cough suppressants are divided into Two groups:  Opioid /Narcotic preparation  Non-Opioid/Non-Narcotic preparation Opioid  Used only for nonproductive coughs  Suppress the cough reflex by direct action on the cough centre in the medulla  Examples:  Codeine  Hydrocodone  Hydromorphone  Codeine is converted in the liver to morphine by specific enzymes.  Some people are rapid metabolizers who may have morphine higher than normal in their blood stream  Higher levels of morphine can result in breathing difficulty, which may be fatal. Adverse effects:  Constipation  Sticky sputum Non-opioid’s  Suppress the cough reflex by numbing the stretch receptors in the respiratory tract and preventing the cough reflex from being stimulated  It has no breathing suppression effect  Examples:  Dextromethorphan Adverse effects:  Dizziness  Drowsiness  Nausea Nasal decongestants  Excessive nasal secretions  Inflamed and swollen nasal mucosa  Primary causes - Allergies - Upper respiratory infections (common cold) Nasal Decongestant Drugs Adrenergic Corticosteroids (Nasal steroids) AntiHistamine Mainly act through  Vasoconstriction  Inhibiting of vascular permeability 1. Adrenergic drugs  1 receptor agonist: phenylephrine Topical application directly into the nares (nasal passages) Prompt onset Potent Adverse effects Rebound effect (after a few days of use if discontinued can have rebound congestion) Tachyphylaxis-rapid decrease in response to a drug after its administration Cough and throat irritation 2- Corticosteroids Beclomethasone Administrated as nasal inhaler Has an anti-inflammatory effect that relieve nasal stuffiness. Precaution and contradictions Viral, bacterial or fungal infections Adverse effects Throat irritation, Dry mouth, Cough 3- Anti-histamines  H1-histamine antagonist  Reverse increased capillary permeability  Edema  Inflammation  Itching caused by sudden increase in histamine release  Also used to treat symptoms of allergies (rhinitis and rash)  Should be given early in the treatment to prevent histamine action Classified to two groups:  First generation :Chlorpheniramine- have an anticholinergic in action Adverse effects Drowsiness Drying of secretion (eye, nose and throat) hypotension  Second generation :Certerizine (Zyrtec)  Selective H1-histamine  less CNS effects (less sedation and less anticholinergic effects Adverse effects Headache Fatigue Dry mouth Asthma  Inflammatory disorder of the airways in which many cells and cellular elements play a role in particular mast cells eosinophil, T-lymphocytes, macrophages, neutrophils, and epithelial cells  The rupture of degranulation of mast cells and the subsequent spilling of their chemical mediators contents cause inflammation response that lead to asthma  Stabilizing the mast cell membrane has antiinflammatory actions that prevent the release of mediators from mast cells and eosinophils.  Factors that exacerbate asthma:      Viral infection Cigarette smoke Exercise and hyperventilation Weather Food, additives, and drugs Agents Used to Treat Asthma Bronchodilators   adrenergic agonists Anti-cholinergic Xanthine derivatives Anti-leukotrienes Anti-inflammatory  Corticosteroids Bronchodilators 1-2 adrenergic agonists  Stimulate 2-adrenergic receptors in smooth muscle of bronchi and bronchioles---- stimulate cAMP----- bronchodilation  First choice in treatment of acute attacks as well as prevention  Quickly reduce airway constriction and restore normal airflow Relief of bronchospasm  Given by inhalation (aerosol)  Salbutamol-short acting 3-6h  Salmeterol –long acting up to 12h Adverse effects Tachycardia Tremor 2-Anti-cholinergic  Acetylcholine (ACh) causes bronchial constriction and narrowing of the airways  Binds to the ACh receptors, preventing ACh from binding bronchoconstriction is prevented, airways are dilated Ipratropium bromide is the only anti-cholinergic used for respiratory disease Slow and prolonged action Given by inhalation for patient intolerant to 2 agonists Used to prevent bronchoconstriction Can be given in combination with 2 adrenergic drugs (salbutamol/ipratroprium) Adverse effects Dry mouth Headache 3-Xanthine Derivatives  A substance found in caffeine, theobromine, and theophylline and encountered in tea, coffee, and colas-Aminophylline (given orally).  Cause bronchodilation by relaxing smooth muscles of the airways (cAMP)  Cause CNS stimulation  Slow onset action and are mostly used for prevention Adverse effects Nausea and vomiting Hyperglycemia Tachycardia 4-Anti-leukotrienes New class of asthma drugs that either inhibits leukotriene synthesis (zileuton) or blocks their receptors (zafirlukast)-also receptor antagonists (LRTAs) called leukotriene Adverse effects Pain Fatigue Nausea Anti-Inflammatory agents Glucocorticoid- Budesonide  Used for chronic asthma  Do not relieve symptoms of acute asthmatic attacks  their effect starts after 6 hours  Oral or inhaled forms  Inhaled forms reduce systemic effects  Decrease mucous secretion, edema and reactivity  Increase responsiveness of bronchial smooth muscle to beta-adrenergic stimulation Adverse effects:  Oropharyngeal candidiasis (thrush)  Dysphonia (hoarseness)  Sore mouth and sore throat