Pharmacological Treatment of Asthma and COPD Flashcards
What are the goals of treatment of asthma?
- no day-time symptoms
- no night-time waking due to asthma
- no need for rescue medication
- no asthma attacks
- no limitations on activity including exercise
- normal lung function (FEV1 and/or PEF >80%)
- minimal side-effects from medication
What is the approach to treatment of asthma?
- start at appropriate level
- achieve early control
- maintain control by stepping up/down when needed
- checking concordance/compliance/adherence at every change
What are the advantages of inhaled administration of asthma medicine?
- direct delivery to site of action
- rapid response with rescue medication
- allows smaller doses than systemic route
- reduces side-effects
What determines the efficiency of the route of administration?
- type and severity of asthma
- particle size of medicine
- inhaler technique
What are the different inhaler devices?
- MDI: metered dose inhaler (press down and breathe in- only 10% delivered to lungs)
- accuhaler: dry powder (fast inhalation, over 5 seconds, patient has to hold breath for 10 seconds after)
- via spacer/aerochamber
What are the advantages of spacers and how does it work?
- gives patients another 10 seconds roughly to breathe in medicine
- improves lung deposition of the medicine
- breaks down the particle size of the drug
- larger particles sit at the bottom of the spacer so smaller particles can enter the smaller airways
Describe how the nebulised route works and the advantages and disadvantages of it
- uses O2, compressed air or ultrasound to break up drug solutions into fine mist
- inhaled in a facemask/mouthpiece
- advantage: gives high doses quickly to give a fast response
- disadvantage: increased risk of side-effects
What are the 5 pharmacological treatment steps for asthma?
- intermittent reliever therapy
- regular preventer therapy
- initial add-on therapy
- additional controller
- specialist therapies
What are the 5 classes of ‘relievers and preventers’ of asthma?
- beta2-adrenoreceptor agonists
- glucocorticoids
- cysteinyl leukotriene antagonist
- methylxanthines
- monoclonal antibodies
Describe the mechanism of action of Beta2-agonists
- step 1 and 3
- short and long acting
- stimulate bronchial smooth muscle receptors, relaxes muscles, dilates airways reducing breathlnessness
- inhibit mediator release from mast cells and infiltrating leukocytes (short-acting)
- increase ciliary action of airway epithelial cells (aids mucus clearance)
Beta2-agonist for step 1
- intermittent reliever
- short acting (SABA) lasts 5 hours
- eg. salbutamol, terbutaline
- reliever
Beta2-agonist for step 3
- initial add on therapy (given combined with inhaled steroid)
- long acting (LABA) up to 12 hours
- eg. salmeterol, formoterol
- given to prevent bronchospasm (at night/exercise) in patients that need long term therapy
What are the side effects of Beta2-agonists?
- sympathomimetic effects (tachycardia/tremor/headache)
- muscle pain/cramps
- electrolyte disturbances (hypokalaemia)
- hyperglycaemia
- paradoxical bronchospasm (very rare)
What drugs are used for step 2, when would you give them and what are the outcomes of it compared to other treatment?
- inhaled corticosteroids
- given if person has symptoms or is using SABA more than 3 times a week
- if waking up at night with wheeze
- if had an asthma attack in last 2 years
- slower onset of action
- longer term effects over months (reduction in airways responsiveness to allergens and irritants)
What is the mechanism of action of inhaled corticosteroids?
- bind to glucocorticoid receptor modifying immune response
- inhibits formation of cytokines (including IL)
- inhibits activation and recruitment of inflammatory cells to airways
- inhibits generation of inflammatory prostaglandins and leukotrienes (reduces mucosal oedema)
- decreases mucosal inflammation, widens airways and reduces mucus secretion)
