Asthma pharmacology Flashcards
What are the two phases in an asthma attack?
- early phase - Bronchoconstriction - due to release of spasmogens (e.g. histamine etc.)
- late phase - bronchoconstriction, inflammation, hyperreactivity, hyperreactivity, hypersecretion.
This is due to infiltration of Th2 cells, eosinophils, monocytes and macrophages because of chemoattractants, secreted by mast cells upon antigenic stimulation.
What does activation of M3 receptors in airways cause?
bronchoconstriction
increased secretions
What is the effect of prostaglandins in inflammation?
vasodilation
bronchoconstriction
What is the effect of leukotrienes in asthma?
chemotaxis, increased permeability, bronchoconstriction.
What is the effect of a beta 2 agonist on the airways?
Bronchodilation
decrease in secretions
What is the mechanism of ipratropium?
Acetylcholine antagonist.
Stops ACh binding to M3 receptors, this causes relaxation of trachealis muscle and therefore bronchodilation.
What is the mechanism of salbutamol?
SABA
short acting beta2 agonist
Causes bronchodilation and a decrease in mucus secretions
often first line in treating asthma.
How does the residual volume change in an asthma pt?
increase
How do we measure FEV?
forced expiratory volume
spirometer
Why is the FEV curve biphasic?
initial stage = release of chemotaxins by mast cells cause infiltration of monocytes, macrophages etc and cause a delayed inflammation and hypersensitivity.
Give an example of a long acting beta antagonist
salmeterol
name 2 muscarinic antagonists used in asthma tx?
ipratropium
tiotropium
What are some of the side effects of muscarinic antagonists?
Nausea, heartburn, constipation
dry mouth
difficulty urinating
eye irritation
tachycardia
What is the use of theophylline?
asthma, bronchodilator
What is theophylline mechanism of action?
Inhibits phosphodiesterase, leading to increased cAMP levels and bronchodilation.
What is the function of leukotriene receptor antagonists?
bronchodilation
give an example of a leukotriene antagonist which can be used in asthma tx?
montelukast
Give an example of glucocorticoids used in asthma treatment
prednisolone
hydrocortisone
beclomethasone
What is the mechanism of action of glucocorticoids?
Reduce cytokine release
stop production of annexin-1 which stops the production of prostaglandin and leukotrienes by inhibiting phopholipase A2.
What are some side effects of using glucocorticoids?
HPA axis suppression (dependence on exogenous
glucocorticoids)
Gastric ulcers
Cushings symdrome
Infection
Give an example of some drugs which can cause asthma attacks
Beta blockers - propanolol, atenolol
Anti-cholinesterases - neostigmine
NSAIDS such as aspirin.
How can NSAIDS cause an asthma attack?
Inhibit COX, so all of the PGH2 is then converted into leukotrienes via lypoxygenase.
