Flashcards in Drugs for COPD and Asthma Deck (20):
What are the two treatment approaches to COPD and asthma?
1. Bronchodilation - via relaxation of airway smooth muscle (i.e. beta agonists)
2. Anti-inflammation - reverse airway mucosal thickening caused by edema and cellular infiltration (i.e. corticosteroids)
What are the two types of asthma and which is associated with allergy?
1. Early onset asthma or extrinsic asthma - associated with allergy in young children
2. Late onset asthma or intrinsic asthma - non-specific factors, stress, or severe exertion
How does binding of the beta-2 receptor result in relaxation of airway smooth muscle?
Gs protein triggers increase in cAMP. cAMP promotes phosphorylation of MLCK to inactive form. If MLCK is inactive, it cannot cause contraction of smooth muscle
How do the M3 receptors in the lungs cause bronchoconstriction and increased mucus secretion?
Gq mechanism causes increase in Ca+2, which binds calmodulin and activates MLCK which causes bronchiolar contraction.
Other than increasing bronchiolar relaxation, how does cAMP increase benefit patients in acute asthmatic attacks?
Inhibits the exocytosis of histamine from mast cells and basophils (cGMP will increase the exocytosis)
Why is alpha receptor activation of epinephrine actually good in anaphylaxis?
Constricts the bronchial mucosal vessel and decreases the blood flow, preventing the mucosal gland from overacting and decreasing congestion / edema
What are the short-acting Beta-2 agonists of consequence?
What are the long-acting Beta-2 agonists of consequence?
When is it good to use a beta-2 agonist vs a corticosteroid?
Beta-2 agonist - only during exacerbations (bronchospasm) or at low levels in combined therapy with corticosteroid
Corticosteroid - Long-term control to prevent exacerbation, or at very high levels in life threatening situations (not good for acute attack)
What are the two cholinergic antagonists used for asthma control and why are they used?
2. Tiotropium (longer-acting)
Used in asthma exacerbations when patient is on a beta-blocker or can't tolerate beta-2 agonists
What is the mechanism of action of Xanthines? Give an example
Inhibit phosphodiesterase, increasing cAMP levels
What are the 5 stages of asthma?
5. Respiratory acidosis
In what stage of asthma are Xanthines used?
Can be used in all stages, may be given IV in later stages. Generally has a synergistic effect with beta-2 agonists.
Why should you use xanthines cautiously? What drug-drug interaction do you worry about most?
Very narrow therapeutic range, can give high probability of seizure and cardiac stimulation which causes arrhythmia and fatal cardiac arrest
Most likely to accumulate due to structural analog -> caffeine
What are the three drugs which have the highest efficacy in long-term corticosteroid management of asthma?
First two are fluorinated to have longer action and less systemic effects
Why is Ciclesonide juicy?
It is activated by two enzymes that are only expressed in upper and lower airway epithelium limiting adverse effects
What are combination inhalers?
Corticosteroid combined with long-acting beta-2 agonist -> not recommended in children less than 12 years old
Why drug is super efficacous in the treatment of mild to moderate extrinsic asthma? How is it taken?
Cromolyn sodium -> prevents mast cell degranulation
Taken via inhalation
What are the leukotriene receptor blockers used only for extrinsic asthma?
1. Montelukast (Taken orally)
2. Past: Zafirleukast -> too many drug-food interactions
Treatment of allergic rhinitis