Ch. 17 Drugs for the Treatment of Respiratory Disorders

Respiratory Diseases:

• Asthma

• Chronic obstructive pulmonary disease (COPD)→ chronic bronchitis, emphysema

• Upper respiratory tract infections

Asthma:

• Reversible airway obstruction

• Associated with reduction in expiratory airflow

• Allergens

• Exercise

• Stress

• Environmental pollution

• Signs include shortness of breath and wheezing

Chronic Obstructive Pulmonary Disease (COPD):

• Irreversible airway obstruction

• Chronic bronchitis is a result of chronic inflammation of the airways and excessive sputum production

• Emphysema is characterized by alveolar destruction with airspace enlargement and airway collapse

Metered-Dose Inhalers (MDIs):

• Medication delivered directly into bronchioles

• Bronchodilator effect is greater than comparable oral dose

• Inhaled dose can be accurately measured

• Rapid and predictable onset of action

• Compact, portable, and sterile

Two types of medication used:

1. beta agonists

2. anticholinergic drugs

Beta Agonists:

Mechanism of Action: Beta agonists stimulate beta-2 adrenergic receptors in the lungs, leading to the relaxation of bronchial smooth muscles and dilation of the airways

Examples: Albuterol (short-acting), Salmeterol (long-acting)

Uses: Primarily used for quick relief of acute bronchospasm (short-acting) and long-term control of asthma and COPD (long-acting)

Side Effects: Can include increased heart rate, tremors, and nervousness

Anticholinergic Drugs:

Mechanism of Action: Anticholinergics block the action of acetylcholine on muscarinic receptors in the lungs, reducing mucus production and relaxing the airway muscles

Examples: Ipratropium(Atrovent-short-acting), Tiotropium (Spiriva-long-acting)

Uses: Often used for maintenance treatment of COPD and sometimes asthma

Side Effects: Can include dry mouth, constipation, and blurred vision

Inhaled short-acting B2 -agonists (asthma & COPD):

• Albuterol (ProAir HFA, Proventil HFA)

• Metaproterenol (generic)

• Levalbuterol (Xopenex HFA)

Inhaled short-acting B2 -agonists/shortacting anticholinergic combinations (COPD):

Albuterol/Ipratropium (Combivent, Combivent Respimat, DuoNeb)

Inhaled long-acting B2 -agonists:

Salmeterol (Serevent Diskus)

Inhaled corticosteroids for Asthma

• Beclomethasone (QVAR)

• Fluticasone (Flovent HFA, Flovent Diskus)

Oral corticosteroids for Asthma

Prednisone (Deltasone, Meticorten)

Adverse effect with chronic use of inhalation _______

Candidiasis

Sympathomimetic or Adrenergic Agents for Persistent Asthma: Inhaled corticosteroids/long-acting B2 - agonists

• Fluticasone/salmeterol (Advair HFA, Advair Diskus)

• Budesonide/formoterol (Symbicort HFA)

Leukotriene Modifiers (LTs):

Leukotriene modifiers, also known as leukotriene receptor antagonists or leukotriene synthesis inhibitors, are medications used to manage asthma and allergies by blocking the effects of leukotrienes, which are inflammatory chemicals produced in the body. These chemicals constrict airways, increase mucus production, swell nasal passageways.

Leukotriene Modifiers (LTs) Examples

Zileuton (Zyflo)

• Life-threatening hepatic injury

Zafirlukast (Accolate)

• Drug interaction with E-mycin and aspirin

• Increases effect of warfarin

• Increases blood level of theophylline

• Life-threatening hepatic injury

Montelukast (Singulair)

• Mood changes

Mast Cell Degranulation Inhibitor: Cromolyn (Intal, Nasalcrom)

• Used only for prophylaxis of asthma

• Not used for an acute asthma attack

• May be used prophylactically by patients with chronic asthma or taken before exercise-induced asthma

Xanthines & Methylxanthines:

These medications relax smooth muscles in the airways

• Theophylline (Theo-Dur, Slo-Bid)-used as a bronchodilator

• Caffeine

• Theobromine

• Theophylline + ethylenediamine = Aminophylline ( more soluble)

• Side effects include central nervous system (CNS) stimulation, cardiac stimulation, increased gastric secretion,

Anti–Immunoglobulin E Antibodies: Omalizumab (Xolair)

A recombinant humanized monoclonal antibody

• Prevents IgE from binding to mast cells and basophils

Agents Used to Manage Upper Respiratory Tract Infections: Nasal Decongestants

Nasal decongestants are adrenergic agonists that act by constricting the blood vessels of the nasal mucous membranes. Many nasal decongestants are available OTC for both local and systemic use. Chronic use may result in rebound swelling and congestion.

• Pseudoephedrine(Sudafed, Sucrets, in Actifed) is used systemically as a nasal decongestant. It is both an a-adrenergic agonist and a badrenergic agonist.

• Phenylephrine(Neo-Synephrine, Sinex, Allerest) is used topically as a nasal spray. It is an a-adrenergic agonist.

• Phenylpropanolamine is used systemically as a decongestant. It is an a-adrenergic agonis6

Agents Used to Manage Upper Respiratory Tract Infections: Expectorants and Mucolytics

• Mucinex ( Guaifenesin)

• Expectorants promote removal of exudate or mucus from respiratory passages

• Liquefying expectorants decrease the viscosity of mucus

• Mucolytics destroy or dissolve mucus

Agents Used to Manage Upper Respiratory Tract Infections: Antitussives

• Codeine-containing cough preparations

• Dextromethorphan (DM in Robitussin DM)