Pharmacology of Respiratory Diseases


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  • Aminophylline is a compound of the bronchodilator theophylline with ethylenediamine in 2:1 ratio. The ethylenediamine improves solubility, and the aminophylline is usually found as a dihydrate.
    Aminophylline is less potent and shorter-acting than theophylline
    Aminophylline: competitive nonselective phosphodiesterase inhibitor[3] which raises intracellular cAMP, activates PKA, inhibits TNF-alpha[4][5] and leukotriene[6] synthesis, and reduces inflammation and innate immunity[6]and nonselective adenosine receptor antagonist.[7]
  • Reference ranges of theophylline in the treatment asthma vary by age, as follows:
    Adults: 5-15 µg/mL
    Children: 5-10 µg/mL
    The reference range of theophylline in the treatment of acute bronchospasm in adults is 10-15 µg/mL.
    The reference range of theophylline in the treatment of neonatal apnea is 6-11 µg/mL.
  • PUD: peptic ulcer disease
  • Pharmacology of Respiratory Diseases

    1. 1. Pharmacology of Respiratory Diseases Prepared by: Dr. Hassan Al-Tomy Reviewed and presented by: Dr. Muna Oqal
    2. 2. Bronchial Asthma Recurrent and reversible shortness of breath Occurs when the airways of the lungs become narrow as a result of: – Bronchospasm – Inflammation of the bronchial mucosa – Edema of the bronchial mucosa – Production of viscid mucus Alveolar ducts/alveoli remain open, but airflow to them is obstructed Symptoms – Wheezing – Difficulty breathing
    3. 3. Asthma Three categories • Allergic • Idiopathic • Mixed allergic/idiopathic
    4. 4. COPD Chronic obstructive pulmonary disease • Applies to chronic bronchitis and emphysema • Obstruction is constant
    5. 5. Agents Used to Treat Asthma • Long-term control – Antileukotrienes – Cromolyn – Inhaled steroids – Long-acting beta2-agonists • Quick relief – Intravenous systemic corticosteroids – Short-acting inhaled beta2-agonists – Ipratropium – Nedocromil – theophylline
    6. 6. Aerosol delivery of drugs – Should produce a high local concentration in the lungs with a low systemic delivery → minimizing side effects – Size of the particles: critical determinant • >10 um – deposited in the mouth & Oropharynx • <0.5 um – inhaled, subsequently exhaled • 1-5 um – allow deposition & most effective
    7. 7. Bronchodilators: Xanthine Derivatives • Plant alkaloids: caffeine, Theobromine, and Theophylline • Only Theophylline is used as a bronchodilator – Examples: • Aminophylline • Theophylline
    8. 8. Xanthines: Action • Smooth muscle relaxation • Bronchodilation • Increased airflow
    9. 9. Xanthines: Drug Effects • CNS stimulation • Cardiovascular stimulation: – Increased force of contraction – Increased HR – Increased cardiac output – Increased blood flow to the kidneys (diuretic effect)
    10. 10. Xanthines: Indications • Dilation of airways in asthmas, chronic bronchitis, and emphysema • Mild to moderate cases of acute asthma • Adjunct agent in the management of COPD
    11. 11. Xanthines: Side Effects • Nausea, vomiting, anorexia • Gastroesophageal reflux during sleep • Sinus tachycardia, extrasystole, palpitations, ventricular dysrhythmias • Transient increased urination
    12. 12. RT Implications: Xanthine Derivatives • Contraindications: history of PUD or GI disorders • Cautious use: cardiac disease • Timed-release preparations should not be crushed or chewed (causes gastric irritation)
    13. 13. Bronchodilators: Beta-Agonists • Large group, sympathomimetic. • Used during acute phase of asthmatic attacks. • Quickly reduce airway constriction and restore normal airflow. • Stimulate beta2-adrenergic receptors throughout the lungs.
    14. 14. Bronchodilators: Beta-Agonists Three types • Nonselective adrenergics – Stimulate alpha-, beta1- (cardiac), and beta2- (respiratory) receptors – Example: epinephrine • Nonselective beta-adrenergics – Stimulate both beta1- and beta2-receptors – Example: Isoproterenol • Selective beta2 drugs – Stimulate only beta2-receptors – Example: Salbutamol
    15. 15. Beta-Agonists: Mechanism of Action • Begins at the specific receptor stimulated. • Ends with the dilation of the airways. – relaxes smooth muscles of the airway and results in bronchial dilation and increased airflow
    16. 16. Beta-Agonists: Indications • Relief of bronchospasm related to asthma, bronchitis, and other pulmonary diseases. • Useful in treatment of acute attacks as well as prevention • Used in hypotension and shock. • Used to produce uterine relaxation to prevent premature labor. • Hyperkalemia—stimulates potassium to shift into the cell
    17. 17. Beta-Agonists: Side Effects Alpha-Beta (epinephrine) • insomnia • restlessness • anorexia • vascular headache • hyperglycemia • tremor • cardiac stimulation
    18. 18. Beta-Agonists: Side Effects Beta1 and Beta2 (Isoproterenol) • Cardiac stimulation • Tremor • Vascular headaches • Hypotension • Anginal pain
    19. 19. Beta-Agonists: Side Effects Beta2 (Salbutamol) • Hypotension OR hypertension • Vascular headaches • Tremor
    20. 20. RT Implications • Monitor for therapeutic effects – Decreased dyspnea. – Decreased wheezing, restlessness, and anxiety. – Improved respiratory patterns with return to normal rate and quality. – Improved activity tolerance. • Decreased symptoms and increased ease of breathing.
    21. 21. RT Implications: Beta-Agonist Derivatives • Salbutamol, if used too frequently, loses its beta2- specific actions at larger doses. • As a result, beta1-receptors are stimulated, causing nausea, increased anxiety, palpitations, tremors, and increased heart rate.
    22. 22. Anticholinergics: Mechanism of Action • Acetylcholine (ACh) causes bronchial constriction and narrowing of the airways. • Anticholinergics bind to the ACh receptors, preventing ACh from binding. • Result: bronchoconstriction is prevented, airways dilate.
    23. 23. Anticholinergics • Ipratropium (Atrovent) and Tiotropium (spiriva) • Slow and prolonged action • Used to prevent bronchoconstriction
    24. 24. Anticholinergics (cont'd( Side effects: • Dry mouth or throat • Gastrointestinal distress • Headache • Coughing • Anxiety
    25. 25. Antileukotrienes • Also called leukotriene receptor antagonists (LRTAs). • Newer class of asthma medications • Three subcategories of agents. • Leukotrienes are substances in the body that cause inflammation, bronchoconstriction, and mucus production. • Result: coughing, wheezing, shortness of breath.
    26. 26. Antileukotrienes (cont'd( Currently available agents – montelukast (Singulair) – zafirlukast (Accolate) – zileuton (Zyflo) Mechanism of Action – Prevent inflammation in the lungs so asthma symptoms are relieved
    27. 27. Antileukotrienes: Drug Effects • Keep bronchial airways relaxed (open) • Decrease mucus secretion • Prevent vascular permeability • Preventing inflammation
    28. 28. Antileukotrienes: Indications • Prophylaxis and chronic treatment of asthma in adults and children older than age 12. • NOT meant for management of acute asthmatic attacks. • Montelukast (Singulair) is approved for use in children ages 2 and older.
    29. 29. Antileukotrienes: Side Effects Headache Dyspepsia Nausea Dizziness Insomnia Liver dysfunction
    30. 30. Corticosteroids • Anti-inflammatory. • Used for chronic asthma. • Do not relieve symptoms of acute asthmatic attacks. • Oral or inhaled forms. • Inhaled forms reduce systemic effects. • May take several weeks before full effects are seen.
    31. 31. Corticosteroids: Mechanism of Action • Stabilize membranes of cells that release harmful bronchoconstriction substances. • These cells are leukocytes, or white blood cells. • Also increase responsiveness of bronchial smooth muscle to beta-adrenergic stimulation
    32. 32. Inhaled Corticosteroids • Beclomethasone • Fluticasone • Budesonide • Mometasone
    33. 33. Inhaled Corticosteroids: Indications • Treatment of bronchospastic disorders that are not controlled by conventional bronchodilators. • NOT considered first-line agents for management of acute asthmatic attacks or status asthmaticus
    34. 34. Inhaled Corticosteroids: Side Effects • Pharyngeal irritation • Coughing • Dry mouth • Oral fungal infections • Systemic effects are rare because of the low doses used for inhalation therapy
    35. 35. Inhaled Corticosteroids: Nursing Implications • Cautious use in patients with diabetes, glaucoma, osteoporosis, PUD, renal disease, HF, edema. • Teach patients to gargle and rinse the mouth with water afterward to prevent the development of oral fungal infections
    36. 36. Mast Cell Stabilizers • Cromolyn (NasalCrom, Intal) • Nedocromil (Tilade)
    37. 37. Mast Cell Stabilizers (cont'd( • Indirect-acting agents that prevent the release of the various substances that cause bronchospasm. • Stabilize the cell membranes of inflammatory cells (mast cells, monocytes, macrophages), thus preventing release of harmful cellular contents. • No direct bronchodilator activity. • Used prophylactically.
    38. 38. Mast Cell Stabilizers: Indications • Adjuncts to the overall management of asthma. • Used solely for prophylaxis, NOT for acute asthma attacks. • Used to prevent exercise-induced bronchospasm. • Used to prevent bronchospasm associated with exposure to known precipitating factors, such as cold, dry air or allergens.
    39. 39. Mast Cell Stabilizers: Side Effects Coughing Sore throat Rhinitis Bronchospasm Taste changes Dizziness Headache
    40. 40. Other Respiratory Agents Mucolytic Agents 1. Acetylcysteine - reduce the thickness and stickiness of purulent and non-purulent pulmonary secretions - antidote for paracetamol poisoning 2. Carbocysteine - act by regulating and normalizing the viscosity of secretion from the mucus cell of respiratory tract - decrease the size and number of mucus producing cells 3. Bromhexine - depolymerization of mucopolysaccharides, direct effect on bronchial glands - liberation of lysosomal enzymes producing cells which digest mucopolysaccharide fibers
    41. 41. Other Respiratory Agents Mucokinetic & Secretolytic 1. Ambroxol - increase respiratory tract secretions - enhance pulmonary surfactant production - stimulates cilia activity Expectorant 1. Vagal stimulants: glyceryl guiacolate, salt solution 2. Direct stimulants: bromhexine, ambroxol Antitussives 1. Narcotic antitussives: heroin, codeine, morphine 2. Non-narcotic antitussive: Dextromethorphan
    42. 42. THANK YOU Mosby items and derived items © 2005, 2002 by Mosby, Inc.