Lower Respiratory Tract Drugs

COPD 

• Emphysema, chronic bronchitis

• Caused by chronic inflammation in respiratory tract due to exposure to irritants (tobacco smoke, environmental pollutants)

• Treatment: Limit exposure to irritants; increase PO fluid intake; breathing exercises; medications—same as asthma treatment

ASTHMA

• Reactive airway disorder—bronchospasm, difficulty breathing

• Mast cell overreactivity—histamine, cytokines, eosinophils released which causes airway edema, smooth muscle constriction, oversecretion of mucus

• Treatment: Avoidance of triggers; management of allergies; avoidance of drugs (ASA, NSAIDS, Beta blockers) that can worsen symptoms

ALPHA & BETA ADRENERGIC AGONISTS

• Albuterol (Proventil, Ventolin)
• Used for bronchodilation
• Stimulates Beta receptors
• Side effects: Beta 1 stimulation (tachycardia, nervousness)
• Terbutaline—similar drug (also used for preterm labor)
• Levobuterol (Xopenex)—similar to albuterol; fewer cardiac side effects; expensive
• Isoproterenol (Isuprel)—Beta 1 & Beta 2 stimulation
• Can be given by IV for severe asthma attacks

• Epinephrine (Adrenalin)
• Stimulates Alpha 1, Beta 1, Beta 2 receptors
• Produces bronchodilation
• Tachycardia, elevates blood pressure; risk of arrhythmias

ANTICHOLINERGICS

• Ipratropium (Atrovent)—Prototype drug
• Prevents bronchoconstriction (end result = bronchodilation)
• Side effects: decreased SLUDGE (dry mouth common)
• Use before inhaled steroid if using dual therapy
• Combination with albuterol=Combivent inhaler

METHYLXANTHINES

• Theophylline (Theo-Dur) & aminophylline—chemically related
• Similar to caffeine—side effects similar
• Narrow therapeutic window
• Not recommended in people with cardiac, renal, hepatic disease or seizures
• Long-acting; mostly used in maintenance of stable asthma

LEUKOTRIENE RECEPTOR ANTAGONISTS

• Montelukast (Singulair)—Prototype drug
• For maintenance/prophylactic therapy of asthma
• Administered by PO route; long-acting
• Decreases inflammatory response; decreases bronchoconstriction
• Few serious side effects; not indicated for acute asthmatic attacks

GLUCOCORTICOIDS (AKA STEROIDS)

• Indicated for acute exacerbations of COPD or asthma
• Action: Decreases inflammatory response
• Many side effects: Elevated blood glucose, increased risk of infection; high doses must be tapered over 1-2 weeks (risk of adrenal suppression); weight gain; fluid retention; osteoporosis & cataracts with long-term therapy
• Systemic effects less with inhaled corticosteroids
• Most common side effect with inhaled: thrush
• Prevent thrush by rinsing mouth after each use

CROMOLYN & NEDOCROMIL

• Cromolyn (Intal)—Prophylactic treatment of asthma
• Chronic therapy; available by PO route
• Inhibits release of histamine
• Side effects:  rebound bronchospasm if abruptly discontinued
• Commonly used in children with asthma