Asthma Treatments Flashcards
Acute severe asthma
Status asthmaticus
Not easily reversed by drugs and can be fatal
Features of asthma
Inflammation of airways
Hyper reactivity of the bronchioles
Results in…
Bronchoconstriction
Mucus secretions
Stimuli that trigger an attack are….
Intrinsic (non atopic)
Excercise, cold air, respiratory infection, atmospheric pollution
Allergic trigger (atopic)
Pollen
Dust
Animal hair
The two phases of an asthma attack are…
Early phase
Bronchospasm
Mast cells release inflammatory mediators
Drugs used- bronchodilator
Late phase
Progressing inflammatory reaction
Drugs used- anti inflammatory
Bronchodilators relax smooth muscle in walls. The types available are… (4)
B2 adrenergic receptor agonists
Theophylline
Muscarinic receptor antagonists
Leukotriene receptor antagonists
B2 adrenergic receptor agonists
Relax smooth muscle
Stop mediator release from mast cells
Salbutamol -short acting
Salmeterol-long acting
Inhaled to increase action in lungs and limit systemic effects
SE: tremor, headaches, tolerance
Theophylline
Inhibits PDE
Second line drug when b2 inadequate
Sustained release tablet
Iv in acute asthma attack
SE: cns stimulating
Cv
Gi tract
Muscarinic receptor antagonists
Ipratropium
Used with b2 and steroids when insufficient
Effect in 30 mins last 5 hours
Inhalation
Well tolerated
Block action of acetylcholine at receptors so relaxation and low secretions.
Acetylcholine in asthma….
Low acetylcholine = few muscarinic receptors activated = smooth muscle relaxed= open airway
Leukotriene receptor antagonists
Montelukast
Zafirlukast
Orally
Prevent exercise /asthma induced asthma
Use in uncontrollable mild to moderate asthma
Prevent actions of LTC4 and LTD4 which are bronchial spasmogens and stimulate mucous
SE: headache , gi problems
Chronic asthma is…
Recurrent attacks of reversible airway obstruction of air flow
Can be controlled with drugs
Glucocorticoids in asthma reduce the production of…..
Cytokines
Spasmogens (TLC4/LTD4)
Leukocyte chemotaxins (LTB4/PAF)
They reduce bronchospasm and the recruitment and activation of inflammatory cells.
Mechanism of glucocorticoid action…
Enter cells Binds to intracellular receptors GRa GRb Receptor complex moves to nucleus Binds to DNA Alters gene transcription
Clinical use of glucocorticoids…
Patients requiring regular bronchodilators to control attacks
Severe asthma
With iv hydrocortisone for acute exacerbations
Short course for deterioration
Long term for some patients
Side effects of glucocorticoids…
Oropharyngeal thrush
Adrenal suppression
Cromoglicate
Anti inflammatory drug
Reduce bronchial hyper reactivity
Effective in asthma caused by antigen/excise
Unpredictable, children respond better
Mechanism of cromoglicate
Not fully understood
Mast cell stabiliser
Reduce neuronal sensitivity to irritants
Inhibit T cell cytokine release
Affect inflammatory cells and mediators
Few side effects
Clinical use of cromoglicate
Inhalation
Prophylactic use
Biological agent used in asthma treatment…
Omalizumab (xolair)
Recombinant DNA-derived humanised igG1 monoclonal anti body
Sub cut injection every 2-3 weeks
Mechanism of omalizumab
Binds to igE
Inhibits binding of this to its receptor on mast cells or basophils
Inhibits igE mediated cascade of asthma
SE: few but severe
Anaphylaxis
Malignancies
Treatments offered for mild asthma
Inhaled b2 agonists when required
Treatment of mild asthma with frequent attacks
Glucocorticoid prophylaxis
B2 agonist when required
Treatment of moderate to severe asthma
B2 agonist with glucocorticoid
In combined inhaler
Plus other drugs when these fail to work
