asthma Flashcards
What is the drug target of salbutamol?
Beta 2 adrenergic receptor on airway smooth muscle cells
What is the primary mechanism of action of salbutamol?
- Agonist at beta 2 receptor on airway smooth muscle cells
- Activation reduces Ca2+ entry preventing smooth muscle contraction
What are the main side effects of salbutamol?
- Palpitations/agitation
- Tachycardia/arrythmias
- Hypokalaemia (at higher doses)
Explain the selectivity for beta 2 from salbutamol
Beta 2 selectivity is not absolute so cardiac (beta 1) effects can be seen
What’s the half-life of salbutamol like?
It’s a short acting beta agonist (SABA) with a half life of 2.5-5 hours
What side effect can be seen via effect on Na+/K+ ATPase?
Hypokalaemia; can be exacerbated by also giving corticosteroids
What is the primary mechanism of action of fluticasone?
- V powerful drugs that do loads
- Directly decreases inflammatory cells:
- Eosinophils
- Monocytes/macrophages
- Mast cells
- Dendritic cells
- Also reduces number of these cells and the cytokines they produce
What is the drug target of fluticasone?
Glucocorticoid receptor
What are the main local side effects of fluticasone?
- Sore throat
- Hoarse voice
- Opportunistic oral infections
What are the main systemic side effects of fluticasone?
Loads more than this
- Growth retardation in children
- Hyperglycaemia
- Decreased bone mineral density
- Immunosuppression
- Effects on mood
Compare fluticasone to cortisol in terms of glucocorticoid receptor affinity
It has a greater affinity for glucocorticoid receptor than cortisol
What is the oral bioavailability of fluticasone?
Oral bioavailability <1% so any systemic delivery via inhaled route is done through pulmonary vasculature
What is the primary mechanism of action of mometasone?
- V powerful drugs that do loads
- Directly decreases inflammatory cells:
- Eosinophils
- Monocytes/macrophages
- Mast cells
- Dendritic cells
- Also reduces number of cytokines they produce
What is the drug target of mometasone?
Glucocorticoid receptor
What are the main local side effects of mometasone?
- Sore throat
- Hoarse voice
- Opportunistic oral infections
What are the main systemic side effects of mometasone?
Loads more than this
- Growth retardation in children
- Hyperglycaemia
- Decreased bone mineral density
- Immunosuppression
- Effects on mood
Compare mometasone’s affinity for glucocorticoid receptor to cortisol
Greater affinity than cortisol
What’s the oral bioavailability of mometasone like?
Oral bioavailability <1% so any systemic delivery via inhaled route is done through pulmonary vasculature
What is budesonide primary mechanism of action?
- V powerful drugs that do loads
- Directly decreases inflammatory cells:
- Eosinophils
- Monocytes/ macrophages
- Mast cells
- Dendritic cells
- Also reduces number of cytokines they produce
What is the drug target of budesonide?
Glucocorticoid receptor
What are the main local side effects of budesonide?
- Hoarse voice
- Opportunistic oral infections
What are the main systemic side effects of budesonide?
Loads more than this
- Growth retardation in children
- Hyperglycaemia
- Decreased bone mineral density
- Immunosuppression
- Effects on mood
Compare the potency of budesonide to fluticasone and mometasone
Less potent than fluticasone and mometasone
What’s the oral bioavailability of budesonide like?
Oral bioavailability 10% so inhaled budesonide will still result in some systemic absorption through GI tract
What is the primary mechanism of action of montelukast?
- Antagonism of CysLT1 leukotriene receptor on eosinophils, mast cells and airway smooth muscle cells
- This decreases eosinophil migration, bronchoconstriction and inflammation induced oedema
What is the drug target of montelukast?
CysLT1 leukotriene receptor
What are the main mild side effects of montelukast?
- Diarrhoea
- Fever
- Headaches
- Nausea or vomiting
What are the serious side effects of montelukast?
- Mood changes
- Anaphylaxis
How long before exercise should montelukast be administered?
For prophylaxis of exercise-induced bronchoconstriction, montelukast should be administered at least 2 hours before initiating exercise
