Bronchodilator Therapy PDF

Bronchodilator Therapy Objectives ˜Compare and contrast bronchoconstriction and bronchospasm. ˜List the three categories of bronchodilators and describe the mechanism of how each class causes bronchodilation. ˜Describe the common adverse effects and contraindications of sympathomimetic, anticholiner...

Bronchodilator Therapy Objectives ˜Compare and contrast bronchoconstriction and bronchospasm. ˜List the three categories of bronchodilators and describe the mechanism of how each class causes bronchodilation. ˜Describe the common adverse effects and contraindications of sympathomimetic, anticholinergic, and methylxanthine bronchodilators. ˜Compare the use of adrenergic, anticholinergic, and methylxanthine bronchodilators in clinical practice. ˜Assess the clinical indications for short-acting and long-acting bronchodilators. ˜A bronchospasm is a reversible contraction of the bronchial smooth muscle, leading to decreased pulmonary function. Bronchospasm is one of the major triggers of bronchoconstriction, but not the only one. ˜Bronchoconstriction is a condition in which the diameter of the airway is reduced or constricted, decreasing expiratory flow. This may be due to bronchospasm, airway inflammation/airway thickening, mucosal edema, or secretions. (or a combination of these) ˜Drug Administration Phase ● ˜Method by which drug is made available to body ● ˜Drugs directly to the respiratory tract use the inhalation route - Liquid solutions, suspensions, or dry powders ● Most common devices used to administer inhaled aerosols are: - Metered-dose inhaler (MDI) - Soft-mist inhaler (Respimat) - Small-volume nebulizer (SVN) - Dry-powder inhaler (DPI) ˜Drug Administration Phase (Cont.) ● ● - Advantages of inhaled aerosols: Aerosol doses are usually smaller than doses for systemic administration Onset of drug action is rapid Delivery is targeted to the organ requiring treatment Systemic side effects are often fewer and less severe Disadvantages of inhaled aerosols: The number of variables affecting the delivered dose Lack of adequate knowledge of device performance Use among patients and caregivers ˜Airway Receptors and Neural Control of Lung ● Sympathetic (adrenergic) and parasympathetic (cholinergic) receptors are in lung ● Neurotransmitters - In sympathetic system is norepinephrine (epinephrine) - In parasympathetic system is acetylcholine ˜Airway Receptors and Neural Control of Lung (Cont.) ● ● ● - Agonists (stimulating agents) Antagonists (blocking agents) Given the following classification: Adrenergic (adrenomimetic) Antiadrenergic Cholinergic (cholinomimetic) Anticholinergic Muscarinic ˜ ˜Adrenergic Bronchodilators ● Indications for use -Short-acting agents ● ● ● ● For relief of acute reversible airflow obstruction Long-acting agents For maintenance bronchodilation in patients with obstructive lung disease Racemic epinephrine To reduce airway swelling after extubation or during croup or epiglottitis To control airway bleeding during endoscopy ˜Adrenergic Bronchodilators (Cont.) ● - Mode of action and effects Alpha-receptor stimulation: causes vasoconstriction and vasopressor effect Beta-1-receptor stimulation: causes increased heart rate and heart contractility Beta-2-receptor stimulation: relaxes bronchial smooth muscle, stimulates mucociliary activity, and has some inhibitory action on inflammatory mediator release ˜Relief of Mucosal Edema ● Sympathomimetics with an a-effect which promotes vasoconstriction (think decongestant), and corticosteroids which have a general anti-inflammatory effect help decrease mucosal edema. ˜Relief of Bronchospasm ● Sympathomimetics (B-adrenergic) ˜ ● Anticholinergics (Parasympatholytics) ˜ ● Methylxanthines (less commonly used) ˜Adrenergic Bronchodilators Classified as: ● Short-Acting ● Long-Acting ● Ultra Long-Acting ˜Short-Acting SABA ● Albuterol (Proventil, Ventolin, Proair) ● Levalbuterol (Xopenex) ˜ ● Epinephrine (systemic) ● Racemic epinephrine (inhaled) ˜ ˜Albuterol SABA ● - Albuterol (Proventil, Ventolin, Proair) HFA: 2 puffs every 4-6 hrs, NEB: 1.25-5 mg every 4-8 hrs. Rapid onset, usually less than 10 mins. Duration: 2-6 hours Indications: Fast-acting bronchodilator for acute bronchospasm ˜Levalbuterol (Xopenex) SABA ● - Levalbuterol (Xopenex) HFA: one to two puffs every 4-6 hrs., NEB: 0.63-1.25mg every 8 hr. Onset: within 15 mins. Duration: 3-8 hrs Indication: Fast-acting bronchodilator for acute bronchospasm - More expensive, usually indicated with cardiac concerns ˜Long-Acting Bronchodilators LABA ● ● ● ● ● ● Arformoterol (Brovana) Formoterol (Foradil/Perforomist) Indacaterol (Arcapta) Olodaterol (Striverdi) Salmeterol (Serevent) Vilanterol up to 12 hrs up to 12 hrs up to 24 hrs up to 24 hrs up to 12 hrs up to 24 hrs Nonselective Sympathomimetics SABA ● - Epinephrine Dose: 0.2-0.5 mg IM (may be repeated) Onset: within 3-5 mins. Duration: 1-3 hours Indications: Status asthmaticus, anaphylaxis ● - Racemic epinephrine Dose: 0.5 mL nebulized (may need to be repeated) Onset: 3 mins. Duration: 30-120 mins Indications: acute mucosal edema, croup, laryngeal edema Adrenergic Bronchodilators (Cont.) ● - Adverse effects (most common) Tremors Headache Insomnia Nervousness Palpitations Pharyngitis Tachycardia Hypokalemia in high doses Adrenergic Bronchodilators (Cont.) ● Assessment of bronchodilator therapy - Based on indication(s) for aerosol agent - Vital signs, breath sounds, and breathing patterns should be evaluated before and after treatment - Patient’s subjective response is important to evaluate Anticholinergic Bronchodilators ● Anticholinergic bronchodilators are also referred to as parasympatholytics, antimuscarinic, or muscarinic antagonists. ● They block or inhibit the effects of ACH at the muscarinic receptors in the parasympathetic system ● Stimulation of the parasympathetic nervous system causes: - Increased secretions - Slowing of HR - Bronchoconstriction - Pupillary constriction M receptors ● M1, M2, M3 receptors are found in the lung tissue and are affected by anticholinergic bronchodilators. ● Use of anticholinergic (parasympatholytic) drugs to block the effects of the parasympathetic system will lead to: - Drying of the pulmonary secretions - Increase of HR - bronchodilation Anticholinergic Bronchodilators ● - Indications for use: Maintenance treatment in COPD Often used during acute asthma attack Combined with a beta-agonist, it is indicated for use in patients with COPD receiving regular treatment who require additional bronchodilation for relief of airflow obstruction Anticholinergic Bronchodilators (Cont.) ● ● - Mode of action Agents act as competitive antagonists for acetylcholine on airway smooth muscle Adverse effects Dry mouth, pupillary dilation, lens paralysis, increased intraocular pressure, increased heart rate, urinary retention, and altered mental state ● 1. ● Side effects seen with anticholinergic aerosol agents SVN, MDI, and DPI (Common) Cough, dry mouth MDI (Occasional) ˜ - Nervousness, irritation, dizziness, headache, palpitation, rash ● SVN and DPI - Pharyngitis, dyspnea, flulike symptoms, bronchitis, upper respiratory infections, nausea, occasional bronchoconstriction, eye pain, urinary retention ˜ Short-acting Antimuscarinic agent SAMA ● ipratropium (Atrovent) - Dose: MDI, 2 inhalations four times daily Neb, 0.5 mg every 6-8 hrs. (more frequently in exacerbations) - Onset: within 15 mins. - Duration: 4-6 hrs. - Indications: COPD (chronic and acute), acute asthma (often combined with albuterol) Long-acting Antimuscarinic Agents LAMA ● ● ● ● Aclidinium Br (Tudorza Pressair) Glycopyrrolate (Seebri Neohaler, Lonhala Magnair Tiotropium Br (Spiriva) Umeclidinium (Incruse Ellipta) 12 hr. 24 hr. up to 24 hr. up to 24 hr. Combined B2 Agonist and Muscarinic-Antagonist Combination ● ● ● ● ● ● Combivent, Duoneb (Ipratropium and albuterol) Anoro Ellipta (Umeclidinium and vilanterol) Bevespi Aerosphere (Glycopyrrolate and formoterol) Stiolto Respimat (Tiotropium and olodaterol) Utibron Neohaler (Olodaterol and glycopyrrolate) Trelegy Ellipta (Vilanterol, umeclidinium, and fluticasone) Methylxanthines ● ● - Caffeine Respiratory stimulant of neonatal apnea (IV) Theophylline Used therapeutically as a bronchodilator Used as an add-on therapy for COPD and asthma Need for monitoring serum concentrations and the potential for serious adverse effects Administered oral or IV Promotes pulmonary vasodilation, coronary vasodilation, cardiac stimulation, enhanced diaphragmatic contractility, CNS stimulation, and diuresis PDE inhibitor ● Roflumilast (Daliresp) - Daliresp is used in COPD patients to reduce the risk of acute exacerbations in patients with severe COPD associated with chronic bronchitis and a history of exacerbations. - Its beneficial effects in COPD are a result of anti-inflammatory properties. - It does not cause bronchodilation and is not a bronchodilator - It is taken orally Magnesium ● IV and nebulized magnesium have been used as an adjunctive bronchodilator in patients with severe, life-threatening asthma exacerbations ● Magnesium sulfate causes smooth muscle relaxation ● It may also reduce neutrophils involved in the inflammatory process and decrease Ach, histamine, and mast cell release. ● Common adverse effects are flushing, fatigue, nausea, headache, hypotension ˜