Respiratory Flashcards
1
Q
β2-selective agonists
A
- Short-acting: Albuterol, Terbutalin, Metaproterenol
- Long-acting: Salmeterol, Formeterol
- Given almost exclusively by inhalation
- Stimulate adenylyl cyclase and increasing cyclic adenosine monophosphate (cAMP) in smooth muscle cells
2
Q
Used in acute episodes of bronchospasm
A
- Albuterol
- Metaproterenol
- Terbutalin
- Epinephrine
3
Q
Used in prophylaxis of asthma
A
- Salmeterol
- Formeterol
- Not used alone! - add to anti-inflammatory therapy
- Inhaled
- Provide bronchodilation for at least 12 hours
4
Q
β2-selective agonists side effects
A
- Skeletal muscle tremor
- Tachycardia, arrhythmia
- Loss of responsiveness
5
Q
Methylxanthines
A
- Caffeine (in coffee)
- Theophylline (in tea) –> the only drug in this group important in treatment of asthma
- Theobromine (in cocoa)
6
Q
Theophylline
A
- Orally active
- Eliminated by P450 drug-metabolizing enzyme (cause increased toxicity in combination with erythromycin, cimetidine)
- Inhibits phosphodiesterase (PDE), thus increase cAMP level –> bronchodilation
- Increased GFR –> increased diuresis
- Decreased mast cell degranulation
- Skeletal muscle contractility (diaphragm)
- May cause seizures or potentially fatal arrhythmias
7
Q
Muscarinic antagonists
A
- Atropine (not used for asthma anymore)
- Ipratropium
- Tiotropium (newer, longer-acting)
- (Oxitropium, Aclidynum, Glizopyrolan)
8
Q
Ipratropium
A
- Competitively block muscarinic receptors in the airways and effectively prevents bronchoconstriction mediated by vagal discharge and mucus secretion
- Effectiv in one to two thirds of asthmatic patients
- May be more effective than β2 agonists in COPD patients
- Drug of choice in bronchospasm caused by β blockers
9
Q
Cromolyn and Nedocromil
A
- Decrease the release of mediators (histamine, PAF, leukotrienes) from pulmonary mast cells
- Have only local effects
- Have no bronchodilator action but can prevent bronchoconstriction caused by allergens
- Asthma is the most important use
- Taken prophylactically
10
Q
Corticosteroids
A
- Local aerosol that are surface-active (first-line treatment for moderate to severe asthma): Beclomethasone, Budesonide, Dexamethasone, Flunisolide, Fluticasone, Mometasone
- IV corticosteroids for status asthmaticus: Prednisolone, Hydrocortisone
11
Q
Corticosteroids; mechanism of action
A
- Decrease inflammatory cascade, reverse mucosal edema, decrease the permeability of capillaries, inhibit release of leukotrienes
- Reduce the synthesis of arachidonic acid by phospholipase A2 and inhibit the expression of COX-2.
- Reduced synthesis of LT –> inhibit bronchoconstriction
12
Q
Leukotriene antagonists
A
- Zafirlukast and Montelukast (LT receptor blockers)
- Zileuton (5-lipoxygenase inhibitor)
- Omalizumab (anti-IgE antibody)
13
Q
Zafirlukast and Montelukast
A
- Antagonist at the LTD4 leukotriene receptor
- Also block LTE4 receptor
- Effective in preventing exercise-, antigen- and aspirin-induced bronchospastic attacks
- Not recommended for acute episodes of asthma
- Have been reported Churg-Strauss syndrome, and allergic granulomatous angiitis
- Zafirlukas: inhibitor of P450
14
Q
Zileuton
A
- Inhibit 5-lipoxygenase, the enzyme that convert arachidonic acid to leukotrienes
- Prevent formation of both LTB4 and the cysteinyl leukotrienes
- Effective in preventing both exercise- and antigen-induced bronchospasm
- Also effective against “aspirin allergy”
- Can cause elevation of liver enzymes
- Inhibitor of P450
15
Q
Omalizumab
A
- Humanized murine monoclonal antibody to human IgE
- Binds to IgE on mast cells and prevent activation by asthma triggers and subsequent release of inflammatory mediators
- Must be given IV
- Used for prophylactic management of asthma
