4.4 Drugs for Asthma and COPD Flashcards
Early phase asthma is associated with bronchospasms. What is the mechanism behind this?
- Allergen interaction with IgE on mast cells = release histamine, leukotriene, B4, and prostaglandin
- Other mediators release IL-4, IL-5, IL-14, macrophages, protein-1a, and TNF-a
- Various chemotaxis and chemokines attract leukocytes (eosinophils and mononuclear cells) preparing for late phase
Early phase asthma is associated with bronchospasms. What is the mechanism behind this?
- Allergen interaction with IgE on mast cells = release histamine, leukotriene, B4, and prostaglandin
- Other mediators release IL-4, IL-5, IL-14, macrophages, protein-1a, and TNF-a
- Various chemotaxis and chemokines attract leukocytes (eosinophils and mononuclear cells) preparing for late phase
Late phase asthma is associated with inflammation. What is the mechanism behind this?
Infiltration of cytokine TH2 lymphocytes + activation of eosinophils
Eosinophils release leukotienes, interleukins IL-3, IL-5, and IL-8, and toxic proteins
Growth factors released from inflammatory cells act on smooth muscle, causing hypertrophy and hyperplasia
According to the AMH, what medication would an asthmatic patient be taking at early phase and late phase?
Early = SABA when req. for symptom relief + low dose ICS
Late (if symptomatic) = ICS + LABA for maintenance and SABA when req. for symptom relief
Beta-2 adrenoreceptor agonists are used in treating early phase asthma. What are the two types of this drug + examples?
- Short-Acting Beta-2 Adrenoreceptor Agonist (SABA) = salbutamol
- Long-Acting Beta-2 Adrenoreceptor Agonist (LABA) = salmeterol and formoterol
How do beta-2 adrenoreceptor agonists work to relieve asthma symptoms?
- Adrenaline + noradrenaline (Ad + NAd) = natural mediators of SNS
- Ad +NAd activate beta-2 adrenoreceptors to relax bronchial smooth muscle
- Beta-2 adrenoreceptor agonists mimic Ad + NAd
- Ad = 20x more potent than NAd
What are the adverse effects of B2 agonists?
Common = tremor, increased heart rate / palpitations, headaches
Serious (at higher dose) = hypokalaemia (low plasma / potassium)
What is anaphylaxis?
Medical emergency
Bronchospasm + hypotension due to mast cell degranulation + histamine release
Adrenaline (epipen) is potentially life saving in the case of anaphylaxis. What is the mechanism behind it?
Adrenaline = non selective adrenoreceptor agonist
Alpha-1 activation = vasconstriction (restores BP)
Beta-2 activation = bronchodilation (reverse airway obstruction)
What are relievers and controllers?
Relievers = short acting agonist to relive symptoms (bronchodilators eg SABA)
Controllers = treatment of underlying causes (anti-inflammatories eg ICS or LABA)
What are exmaples of inhaled corticosteroids (ICS)?
Budesonide
Fluticasone
What are corticosteroids?
Mimic cortisol with minimal aldosterone activity
Glucocorticoids
Cortisol is an endogenous hormone which can regulate many physiological processes and one major immune system process. How do different levels of corticosteroids impact these processes?
Low levels = physiological concentrations = improve immune function
High levels = pharmacological concentrations = potent anti-inflammatory agents and immunosuppressants
Steroids act on nuclear receptors to alter gene transcription, this is a slower process than via other receptors. What are 4 common receptors and their activation time scales?
- Ligand-gated ion channels (ionotropic receptors) = milliseconds
- G protein coupled receptors = seconds
- Kinase-linked receptors = hours
- Nuclear receptors = hours
How do glucocorticoids (ICS) alter production and release of inflammatory mediators?
- Decrease production of prostanoids via suppression of COX II and arachidonic acid release
- Decrease production of cytokines
- Decrease histamine release + other mediators from basophils and mast cells
- Increase synthesis of anti-inflammatory factors