Module 2: Asthma & COPD Flashcards
Asthma
Chronic inflammatory lung disorder
Characterized by:
- Reversible airway obstruction
- Airway inflammation
- Hypersensitivity (increased airway responsiveness to stimuli)
S/S: Coughing, wheezing, difficulty breathing, and chest tightness
One-half of pts that experience asthmatic symptoms are due to allergens (other half is idiopathic)
COPD
Chronic, progressive, and largely irreversible lung disorder
Underlying pathologic processes:
- Emphysema: destruction of alveolar septa and loss of elastic recoil of bronchial walls
- Chronic bronchitis: bronchial edema, hypersecretion of mucus, and bacterial colonization of airways
- Alpha-1 antitrypsin deficiency (3%)
Characterized by:
- Airflow restrictions
- Inflammation
S/S: Chronic cough, sputum, SOB, and poor exercise tolerance
Asthma Goals of Therapy
Asthma therapy goals:
1. Prevent symptoms/exacerbations
- Decrease use of short-acting beta-2 agonist rescue meds.
- Maintain normal lung function and limit reduction of lung function over time
- Decrease ED visits/hospitalizations
- Minimize AEs of therapy
- Smoking cessation (for COPD in particular)
Inhalation Dosage Forms
4 types of dosage forms:
- Metered-dose inhaler (MDI)
- Respimat
- Dry-powder inhaler (DPI)
- Nebulizer
Advantages of inhaled drug therapy:
1. Therapeutic effects are delivered to site of action
- Systemic effects are minimized
- Rapid relief of acute attacks
Metered-dose inhaler (MDI)
Consists of a pressurized canister of propellant with drug suspension that delivers a measured amount of med.
MDI with spacers are ideal for those with impaired coordination to actuate the device and breathe
Only about 10% of the drug reaches the lungs without a spacer (90% of the dose is either swallowed or stays in the oropharynx)
Respimat
Delivers the drug in a fine mist (smaller particles allow for greater deposition into the lungs)
They do NOT use propellant (like MDIs); the device is actuated by the user — thus, requires some coordination, but not to the same degree of MDIs
Issue: Strength and dexterity are required to assemble new cartridges
Dry-Powder Inhaler (DPI)
The med. is in a dry, micronized powder form; and the device is activated when pts inhale from the device (thus, there is no need for hand-breath coordination)
Issue: Difficult for pts who do not have the ability to deeply inspire (i.e. children <4 yrs. of old)
Nebulizer
Not ambulatory; drug solution is converted into a mist (the droplets are much finer than other dosage forms)
Asthma Drugs
Anti-inflammatory drugs:
- Corticosteroids
- Leukotriene modifiers
Bronchodilators:
- Beta-2 agonists
- Methylxanthines
- Anticholinergic drugs
Anti-inflammatory Drug #1: Corticosteroids
AEs (Inhaled):
- Adrenal suppression (most serious) — prolonged, high doses decrease the ability of the adrenal cortex to produce its own glucocorticoids
- Oral candidiasis
- Dysphonia (difficulty speaking; hoarseness) — drug can deposit in the oropharynx
- Growth suppression
- Bone loss
- Cataracts/glaucoma
AEs (Oral):
- Adrenal suppression
- Osteoporosis
- Hyperglycemia
- PUD
- Growth suppression
- Fluid retention
Med. safety concerns:
- IV or PO for acute exacerbation — delayed anti-inflammatory action (6-8 hours)
- Inhaled for chronic management — full response after 2-4 weeks of treatment
RN implications:
- Educate — PREVENTATIVE (does NOT abort acute attack); not PRN
- Proper ICS technique with spacer — inhale beta-2 agonist 5 min. before use to increase drug delivery; and rinse with water and gargle after use to prevent thrush
Anti-inflammatory Drug #2: Leukotriene Modifiers
Prototype: Monteleukast
MOA: Antagonist at leukotriene receptors; blocks activation by leukotrienes (enhance inflammatory response)
Therapeutic use:
- Chronic asthma
- COPD with reactive component
AEs (Generally well tolerated):
- Churg-Strauss syndrome: vasculitis commonly associated with skin and lung problems — when steroid dose is reduced
- Neuropsychiatric effects (rare)
RN implications:
- Give once daily, with or without food
- Ideal for pts that cannot use glucocorticoids
Bronchodilator #1: Short-Acting Beta-2 Agonist (SABA)
Prototype: Albuterol
MOA: Activates beta-2 receptors on smooth muscle cells of bronchial tree, causing muscular relaxation and bronchodilation (minimal beta-1 activity)
Therapeutic use:
- PRN to abort asthmatic exacerbation
- Prevent exercise-induced asthma attack
- COPD
AEs:
- Beta-1 (inhaler overuse): Tachycardia, arrhythmia, hyperglycemia
- Beta-2 (high doses): Tremors, hypokalemia (insulin shifts potassium into cells)
- Tolerance development with frequent use
RN implications (Education on MDI technique):
- Shake canister thoroughly
- Breathe out
- Place mouthpiece between lips
- Tilt head back
- Actuate inhaler and breathe slowly
- Hold for full breath (count to 10)
- Repeat after 1-5 min. if needed
- Clean mouthpiece
- Discard after used pre-specific number of doses
Bronchodilator #1: Long-Acting Beta-2 Agonist (LABA)
Prototype: Salmeterol; with Fluticasone
Therapeutic use: Long-term control (should not be used as mono-therapy)
AEs (same as SABAs):
- May increase risk of death when used as mono-therapy (refutable)
- Not used to stop an acute asthma attack
RN implications: Educate difference between use of rescue and controller inhalers
Bronchodilators #2: Methylxanthines
Prototype: Theophylline
MOA: Inhibits phosphodiesterase, and indirectly stimulates beta-1 and beta-2 receptors; bronchodilation and decreased inflammation
Therapeutic use:
- Aminophylline (more soluble) usually used IV in severe exacerbations
- Chronic asthma
Narrow therapeutic index — monitored by drug levels (5-15 mcg/ml is normal, >20 is associated with toxicity)
AEs:
- N/V and anorexia
- HA and dizziness
- CNS stimulation — caffeine-like symptoms (seizures, dysrhythmias, tachycardia in overdose >30)
Overdose management:
- Discontinue use
- Oral charcoal
- Treat dysrhythmias with verapamil or lidocaine
Individual variation: Liver disease and HF
DDIs:
- Decrease metabolism: Erythromycin & fluoroquinolone (antibiotics)
- Increase metabolism: Smoking & inducers
RN implications:
- Do not double following dose if missed
- Do not crush/chew ECT or SR formulation
- Report early S/S of toxicity — N/V/D, HA, and dizziness
**Older drug not used as frequently (ICS are much safer and effective); and not recommended at all for COPD
Bronchodilator #3: Short-Acting Anticholinergics (SAMAs)
Prototype: Ipratropium
MOA: Blocks muscarinic receptors on bronchial smooth muscle leading to bronchodilation
Therapeutic use:
- COPD
- Acute asthma exacerbation — SAMA added in conjunction with SABA (if severe)
- Onset: 15 min. (SABA onset is 2-5 min.), Duration: 4-6 hours
AEs:
- Dry mouth
- Pharynx irritation
