3 Asthma and COPD Flashcards
Asthma is primarily a disease of ________
Inflammation
Involves narrowing of the small airways and an increased response to stimuli
Treatment strategies for asthma include …
Dilation of airways
DECREASE INFLAMMATION**
Prevention
Bronchioles are constricted by _________ and relaxed by ________
Cholinergic innervation
Beta-2 receptors (stimulated by epi, not NE)
What are the different mediators of bronchial asthma?
Nerves (Acetylcholine, Neurokinin A and Substance P) and Histamine —> bronchoconstriction, microvascular leakage, and mucus secretion
Cytokines (cysteinyl leukotrienes, Leukotrienes B, and platelet activating factor) —> inflammatory cell infiltration and activation
Cationic proteins and reactive O2 metabolites —> epithelial damage
Symptoms of asthma
WHEEZING - but not all asthmatics wheeze***
Tightness, burning feeling, SOB
Mucous
Allergens, exercise, cold air, pollution (COCKROACHES)
COPD is characterized by…
Chronic bronchitis
Inflammation and irritation of lung passages
Cilia immobilized, particles not kept out
Goblet cells make more mucous
Plugged bronchioles susceptible to infection
Airways narrowed
Chronic cough
Emphysema is characterized by…
Breakdown of alveoli walls —> fewer, larger alveoli —> less surface area for gas exchange —> fibrosis, loss of elasticity —> difficulty breathing
What is the most widely used treatment for asthma?
B2 selective receptor agonists
How do B2 receptor agonists work?
B2 receptors increase cAMP —> relax airway smooth muscle/inhibit histamine release from mast cells
How are B2-agonists administered?
Generally inhaled
Aerosol nebulizer and oral forms available too
Can be injected in emergency situations
Examples of B2-agonists
ALBUTEROL Levalbuterol Pirbuterol Terbutaline Bitolterol
Characteristics of short acting B2 agonists (ie Albuterol)
Effects generally last 4-6 hours
Act IMMEDIATELY
Stops an attack in progress
Usually inhaled
What is the prototype long-acting B2-agonist?
Salmeterol
Used for prevention and prophylaxis rather than acute treatment
How is Salmeterol used?
For prevention and prophylaxis
Decreases nocturnal asthma
Characteristics of Salmeterol (LABA)
Effects take 20-30 min (so not for attack in progress but for prevention)
Should always be combined with a steroid (ie Advair)
Why are long-acting B2 agonists (ie Salmeterol) combined with a steroid?
To counteract the down regulation of B2 receptors with long term use
Side effects of long-acting B2 agonists
Tachycardia Nervousness Dizziness (usually short term) Tremor (if using orally) Tolerance (use a steroid if given chronically)
Muscarinic antagonist used for patients who are intolerant of B2 agonists
Ipratoprium (Atrovent)
Used for COPD, not so much for chronic asthma (though can be used in attacks)
Pharmacokinetics of Ipratroprium (Atrovent)
Inhaled
Poorly soluble —> not absorbed (so few systemic effects)
Other muscarinic antagonists (other than Ipratropium)
Combo with albuterol (Combivent)
Belladonna cigarettes
Drug of last choice for asthma
Theophylline - it’s like drinking 5 c of coffee lol
MOA for Theophylline
Increases cAMP - phosphodiesterase inhibitor
Blocks adenosine receptor
Relaxes smooth muscle and stimulates CNS/heart (decreases fatigue of the diaphragm
How is Theophylline used?
For asthma or COPD not controlled by B-agonists or muscarinic antagonists
Long-acting forms generally used
Why is Theophylline the drug of last choice?
LOW THERAPEUTIC INDEX - blood level important and may vary with genetics
WATCH FOR DRUG INTERACTIONS (esp CIMETIDINE)
