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What are the 2 classes of drugs used to treat asthma?
- Bronchodilators
- Anti-inflammatories
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What are the 4 types of bronchodilators?
- 1. Beta 2 agonists
- 2. Xanthine drugs
- 3. Cysteinyl-leukotriene receptor antagonists
- 4.Muscarinic antagonists
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What are the 2 types of anti-inflammatories used to treat asthma?
- 1. Corticosteroids
- 2. Cromoglicate
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Beta 2 agonist description
- Potent Bronchodilators
- Relax SM directly
- Most effective drugs for acute asthma
- Can be Short or Long acting
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Short acting Beta 2 agonist?
- Salbutamol
- Rapid onset of action
- Taken as needed
- Inhaled
- Not suitable as sole therapy
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Long acting Beta 2 agonist?
- Salmeterol
- Taken as preventative
- Inhaled
- Not suitable for acute attacks
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Xanthine drugs summary
- Administered orally or IV
- Act directly on the SM to cause bronchodilation
- Inhibit phosphodiesterases- altering cAMP or cGMP, causing adenosine receptor antagonism
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An example of a Xanthine drug?
- Theophylline
- Rapid onset of action
- Symptomatic relief
- Not suitable for sole therapy
- Low therapeutic index
- S/E's include GIT upset, CNS effects and dysrhthmias
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Cysteinyl-leukotriene antagonist summary
- Relax SM directly to cause bronchoconstriction
- Treats both stages of asthma attack
- Administered orally
- High affinity cysteinyl-leukotriene receptor antagonism
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Example of cysteinyl-leukotriene receptor antagonist?
- Montelucast
- Used for mild asthma, only has 1/3 of Salbutamol's effects
- Used as add on therapy for beta 2 agonists or steroids
- Few side effects (GIT upset)
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Muscarinic antagonist summary
- Weak bronchodilators
- Inhaled
- Compete with ACh at M3 receptor
- Very few side effects
- Used in children
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Example of a muscarinic antagonist?
Ipratropium Bromide
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Corticosteroid Summary
- Used for moderate and severe asthma
- Moderate- orally. Severe- IV.
- Bind steroid receptors and influence gene transcription to decrease cytokine production and increase beta 2 receptor production.
- Decrease inflammatory response, bronchial reactivity and mucosal secretion.
- Increases airway diameter.
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Example of Inhaled Steroid?
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Example of systemic steroid?
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Cromoglicate summary
- Cromoglicate
- Used as a preventative, useless during an attack
- Blocks bronchoconstriction but doesn't cause bronchodilation
- Inhaled
- Mechanism largely unknown (decreases histamine release?)
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