Resp Pharm - Asthma Flashcards
What are aims of asthma control?
Minimise symptoms during day and night Minimise need for reliever medication No exacerbations No limitation on physical activity Normal lung function
What is step 1 of asthma control?
For mild intermittent asthma
Short acting β2 agonists - salbutamol, terbutaline
Used for symptom relief via bronchodilation
Used as required
Why should β2 agonists not be used regularly?
Can lead to increased mast cell degranulation response to allergens
What are some side effects of β2 agonists?
Tachyarrhythmias
Tremors
Hypokalaemia
Anxiety
What is step 2 of asthma control?
Regular prevention therapy - inhaled corticosteroids
Targets eosinophilic inflam
Inhibits translocation of transcription factors => decreased inflam mediators
What is step 3 of asthma control?
Add on therapy
Long acting β2 agonists
What needs to be checked before step 3 of asthma control?
Check inhaler technique
Check pt compliance
Eliminate trigger factors
What are the actions of LABA in asthma control?
Reduce asthma exacerbations
Improve symptoms
Improve lung function
Not anti-inflammatory, need to be given with ICS
Why are LABA and ICS given in a single inhaler?
Easier use
Better compliance
Only one prescription to worry about
Cheaper to use 1 inhaler
What are some alternative step 3 add-ons in asthma control?
High dose ICS
Leukotriene receptor antagonists
Methylxanthines
Long acting anticholinergics
What is the MOA of leukotriene receptor antagonists?
Block effects of leukotrienes in the airways
Inhibit bronchoconstriction, mucus secretion and mucosal oedema
What are some examples of leukotriene receptor antagonists?
Montelukast
Zafirlukast
What are some side effects of leukotriene receptor antagonists?
Angioedema Dry mouth Anaphylaxis Arthralgia Fever GI upset Nightmares
What is the MOA of methylxanthines?
Antagonise adenosine receptors
Increase cAMP
What are some examples of methylxanthines?
Theophylline
Aminophylline
What are some complications from methylxanthines?
Frequent side effects:
Nausea, headache, reflux
Life threatening:
Arrhythmias, fit
Drug interactions:
Levels increased by CYP P450 inhibitors
What is an example of a long acting anticholinergic?
Tiotropium bromide
What are long acting anticholinergics used for?
Exacerbations of asthma and COPD
What are some side effects of long acting anticholinergics?
Dry mouth
Urinary retention
Glaucoma
What is step 5 of asthma control?
Oral steroids
Biological therapies
What is anti-IgE (omalizumab) MOA in asthma?
Prevent IgE binding to IgE receptor
IgE can’t cross link and therefore activate mast cells
What is the MOA for anti-IL5 (mepolizumab, reslizumb) therapy?
IL-5 is a growth factor for eosinophils
Therefore inhibiting it reduces the number of eosinophils in the airways and blood
When should stepping down of asthma control happen?
When asthma is controlled
Pts should be maintained at the lowest possible dose of inhaled steroid
Describe delivery of drug particles via inhalers
Large particles - deposited in mouth and oropharynx
Intermediate particles - settle in small airways tf most effective
Small particles - inhaled to alveoli and exhaled w/o being deposited in the lungs
How should acute severe asthma be treated?
High flow oxygen - keep sats at 94-98%
Nebulised salbutamol - oxygen driven
40mg PO prednisolone/100mg IV hydrocortisone
If not responding add nebulised ipratropium bromide
IV aminophylline if no improvement
What is the MOA of corticosteroids in treating asthma?
Decrease bronchial mucosal inflammation
What is the MOA of theophylline?
Inhibit phosphodiesterase => increased cAMP levels => bronchodilatation
Requires ECG monitoring and measurements of serum levels if given IV
