Pharmacology of Asthma Flashcards
Name 3 groups of medications used to control the symptoms of asthma.
- Beta Agonists/Sympathomimetics
- Muscarinic Agonists/Anticholinergics
- Xanthines
Name 3 classes of medications used to control and prevent future asthma exacerbations.
- Corticosteroids
- Antileukotrienes
- Anti-IgE Ab
What medication do you use to diagnose asthma?
Methacholine “Challenge”
Corticosteroids
Mechanism of Action
target is glucocorticoid receptor in cytoplasm
(1) inhibits phospholipase A2
decreases synthesis of all cytokines (PGEs, LTs)
(2) inactivates NF-κB
decreases transcription of TNF–α & other cytokines
(3) stimulates synthesis β2R in lung, nasal mucosa
co-administer with long-acting β2 agonists (prevents downregulation of β2R via β2 agonists)
Oral Corticosteroid
Use and Toxicity
severe acute exacerbations (IV)
1st line therapy for chronic asthma (PO)
weight gain (nuchal hump, moon facies), mood alteration, muscle twitches, insomnia, bulging eyes
Inhaled Corticosteroids
Use and Toxicity
1st line therapy chronic asthma
slow onset (MDI)
glaucoma, cataracts, osteoporosis, oral candidiasis, dysponia (hoarsness)
Prednisone
Methylprednisolone
oral corticosteroids
Beclomethasone
inhaled corticosteroid
Fluticasone
inhaled corticosteroid
Budesonide
inhaled corticosteroid
Antileukotrienes
Use and Toxicity
exercise-/aspirin-induced asthma
can be combines with corticosteroids (PO)
monitor hepatic enzymes
moderate CYP1A2 inhibitor
Montelukast
block leukotriene receptors (LTD4 receptor)
bronchodilation + anti-inflammatory
Zafirlukast
block leukotriene receptors (LTD4 receptor)
bronchodilation + anti-inflammatory
Zileuton
inhbits 5-lipoxygenase pathway
blocks arachidonic acid -> leukotrienes
LTB4 = attracts neuts; LTC/D4 = bronchoconstrict
Omalizumab
allergic asthma resistant to inhaled steroids and long-acting β-agonists
monoclonal anti-IgE Ab
binds unbound serum IgE, blocks IgE from binding to FcεRI on mast cells
eventually decreases levels of circulating IgE
subcutaneous injection, expensive
URI, headaches
Name the non-selective B agonists and their toxicity.
Epinephrine, Isoprotenerol
tachycardia, arrhythmia, angina
Selective Beta Agonist Mechanism of Action
relaxes bronchial smooth m. (β2)
bind Gs -> increase cAMP -> bronchodilation
other effects - increase surfactant, decrease mediator release, decrease microvasculature leakage
Short-Active B Agonist
Use and Toxicity
1st line for acute exacerbations
(MDI, nebulizer)
β1 (&α) agonism - HTN, angina, vomiting, vertigo, CNS stimulation, dryness/irritation of oropharynx
Long-Acting Beta Agonist
Use and Toxicity
1st line prophylaxis chronic asthma
50X more selective than albuterol
coughing, tremor, arrhythmia, angina, headaches, hives, hypoK
Name the SABAs
Albuterol
Terbutaline
Metaproterenol
Name the LABAs
Salmeterol
Formoterol
Name the three muscarinic antagonists, their uses, and relative toxicities.
Atropine - many systemic side effects
Ipratropium - short-acting
Tiotropium - long-acting
Iprotropium and Tiotropium have rare side effects - dry mouth, dry bronchial secretions, urinary retention.
Xanthines
Mechanism of Action
Use and Toxicity
(1) inhibits phosphodiesterase
increases cAMP (via decrease in cAMP hydolysis)
promotes bronchodilation
(2) blocks actions of adenosine
decreases bronchoconstriction
Use w/ asthma refractive to other medications; use is limited due to narrow therapeutic index.
cardiotoxicity, neurotoxicity
toxicity especially <1 yr olds
(hypoTN, seizures, arrhythmias, nervousness and tremor)
*Many drug intercations - metabolized via cytochrome P450
Theophylline
aka aminophylline
xanthine
