Flashcards in Drug control in asthma Deck (51):
What is asthma?
Recurrent reversible obstruction of airflow in airways in response to non-noxious stimuli
Difficulty in breathing; wheezing; cough
What are reasons in having asthma?
Trigger also required
Allergic in >30%
Post-viral (after infection)
Psychogenic (e.g. stress can be an asthma trigger)
How many people are being treated for asthma in Scotland?
How many deaths a day are caused by asthma in the UK?
5 deaths/day (2000/yr)
What is extrinsic asthma?
What is intrinsic asthma?
What are triggers of asthma?
What is the immune system?
Guards against bacteria, viruses, cancer and parasites. Normally a protective mechanisms
What is an antigen?
Protein or modified protein
How is antibody synthesis induced?
By monocytes (blood) macrophages, lymphocytes, mast cells- IgE
What is the equation for the immune reaction?
A/g + A/b --> immune reaction
What does cell-fixed a/b provide?
What chemical mediators (cytokines) are released by the cell?
Prostaglandins (PG) --> recruit other cells to the site of infection
Platelet activating factor )PAF)
What are the effects of cytokine mediators?
Oedema- fluid leaks out of tissue, causes congestion
Smooth muscle contraction- contraction of bronchioles
What is an allergy?
An inappropriate immune response
Form of reaction, mediators involved, vary in different tissues
What are some effects of an allergic reaction?
Skin- rash, itch
Eyes, nose- hypersecretion
What are the stages of asthma?
What is the intermediate stage of asthma?
Bronchoconstriction (airways constrict), may or may not be vasodilation
Anaphylaxis leads to death
What are the late stages of asthma?
Hyper secretion --> mucus
Bronchoconstriction and hyperreactivity
What does is mean if there is an increase in FEV1 in lungs?
Treatment is working, lungs are getting better
What is innervation of the lungs?
Non-adrenergic non-cholinergic (NANC)
Sensory- irritation--> reflex constriction via parasympathetic
What are upper airways constricted by?
Ach via M3 receptors
What are M3 receptors?
What constricts the lower airways?
What relaxes the lower airways?
NANC transmitters (e.g. NO) and circulating adrenaline (beta 2)
What is not in the airway muscle?
Sympathetic nerve supply
What constricts blood vessel smooth muscle?
NA from sympathetic nerves (alpha 1)
What relaxes blood vessel smooth muscle?
Circulating adrenaline (beta 2)
What system does mucus secretion decrease?
What system does mucus secretion increase?
Parasymathetic system, inflammatory mediators and chemical/physical stimuli
What is the immediate phase of drug therapy?
Smooth muscle relaxants (treat bronchospasm)
What is the late phase of drug therapy?
Steroids (treat inflammation)
What drugs are used to treat asthma?
Glucocorticoids (anti-inflammatory steroids)
What are beta-adrenoceptor agonists?
Alpha + beta agonist
What do B1 adrenoreceptors agonists affect?
What do B2 adrenoreceptor agonists affect?
What is salbutamol?
Beta 2 only
Inhaled aerosol or powder
What does saltbutamol do?
What is the mechanism of saltbutamol?
Increases adenylate cyclase
Decreases Ca2+ entry
What are examples of drugs for muscarinic antagonists?
What does Ipratropium do?
N+ poor absorber
Blocks bronchoconstriction due to parasympathetic reflex
More useful in bronchitis
What does Tiotropium do?
Prolonged (24hr) M3 selective muscarinic antagonist
Better than the older ipratropium
What is theophylline?
How does theophylline relax smooth muscle?
Inhibition of phosphodiesterase
Increases release of NA and Adr
What are some possible serious side effects of theophylline?
Arrythmia, convulsions, low TI
What benefits are antihistamines?
Little benefit in asthma (much more in hayfever etc)
What do antagonists of leukotrienes (LTs) do?
Drugs to block either the LT receptor or the synthesis of LTs
What is an example of a useful glucocorticoid (anti-inflammatory steroids)?
Beclomethasone- very important as prohphylactic
How do glucocorticoides suppress immune system?
Decreases lymphocyte and mass cell number
Decreases mediator synthesis and release
Decreases b.v. permeability
What is the glucocorticoid mechanism?
RNA fro lipocortin (Annexin-1)