Respiratory pharmacology Flashcards
Define asthma
- Chronic inflammatory airway disease
- Intermittent airway obstruction
- Hyper-reactivity of small airways
- Reversible (spontaneously or due to drugs)
- heterogenous disease
What are the aims of asthma control?
- Minimal symptoms during day at night
- Minimal needs for reliever medication
- No exacerbations
- No limitation of physical activity
- Normal lung function
- Early control with stepping up or down as required
What do we need to check before stepping a patient’s asthma treatment up?
- Adherence
- Inhaler technique
- Remove triggers
Give a brief outline of the treatment ladder for asthma
- Regular preventer - low dose ICS
- Initial add-on therapy - add inhaled LABA to low dose ICS
- Additional controller therapies - consider increasing ICS to medium dose or adding LRTA
- Specialist therapies
What indicates that a patient needs to move up the treatment ladder for asthma?
- All asthma patients are given a short acting B2 agonist to use as needed
- Consider moving up if using 3+ doses per week
What are the current NICE guidelines for managing asthma in adults?
- Add LRTA (leukotriene receptor antagonist) after initial low dose LABA
- LRTA is cheaper than LABA
- Though LABA is more effective
Give some examples of inhaled corticosteroids
- Beclomethasone
- budesonide
- Fluticasone
What is the mechanism of action of inhaled corticosteroids?
- Pass through plasma membranes
- Activate cytoplasmic receptors
- Activated receptor passes into nucleus to modify transcription
What are the effects of inhaled corticosteroids on the airways?
- Reduces mucosal inflammation
- Widens airways
- Reduces mucus
- Reduces symptoms, exacerbations and prevents death
What are the adverse side effects of inhaled corticosteroids?
- Can cause a local immunosuppressive action - candidiasis, hoarse voice
What are the contraindications for inhaled corticosteroids?
- Pneumonia risk possible in COPD at high doses
What are the DDIs of inhaled corticosteroids?
- There aren’t really any
Which genes are activated by inhaled corticosteroids?
- Increased B2 receptors
- Anti inflammatory mediators
- Also inhibit release of arachidonic acid
Which genes are repressed by inhaled corticosteroids?
- Those that code for inflammatory mediators
- E.g. interleukins, chemokines, cytokines
Outline the pharmacokinetics of inhaled corticosteroids
- Poor oral bioavailability
- Slow dissolution in aqueous bronchial fluid
- High affinity for glucocorticoid receptor
What happens when a steroid is absorbed p.o.?
- Transported from stomach to liver by hepatic portal system
- Almost complete first pass metabolism
Give some examples of fast-acting B2 agonists?
- Salbutamol and terbutaline (short lasting)
- Formoterol (long lasting)
Give some examples of long-acting B2 agonists?
- Salmeterol (long lasting)
What are the different types of B2 agonists?
- Short acting B2 agonists (SABA) - symptom relief through reversal of bronchoconstriction
- Long acting B2 agonists (LABA) - add on therapy to ICS and SABA
What is the mechanism of action of B2 agonists?
- Major action on airway smooth muscle
- Also increase mucus clearance by action of cilia
- Prevents bronchoconstriction prior to exercise