Asthma Pharmacology Flashcards by rachael a

What are the drugs for asthma?

salbutamol
fluticasone
mometasone
budesonide
montelukast

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What is the drug target for salbutamol?

Beta 2 (β2) adrenergic receptor

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What is the mechanism of action for salbutamol?

Agonist at the β2 receptor on airway smooth muscle cells. Activation reduces Ca2+ entry and this prevents smooth muscle contraction.

it is a bronchodilator

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What are the main side effects of salbutamol?

Palpitations/ agitation
Tachycardia/ Arrythmias
Hypokalaemia (at higher doses)

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What is the half life of salbutamol?

Salbutamol is a short acting beta agonist (SABA). It’s half life is 2.5-5hours.

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Is the beta 2 selectivity of salbutamol absolute?

Beta 2 selectivity is not absolute – as a result, cardiac (beta 1) effects can be seen.
Hypokalaemia can be caused via an effect on sodium/ potassium ATPase. This effect can be exacerbated by coadministration with corticosteroids

(B1 is for the heart, one heart, b2 is for the lungs, 2 lungs (pneumonic to remember))

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What is the drug receptor of fluticasone?

Glucocorticoid receptor

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What is the mechanism of action for fluticasone?

Very powerful drugs. Multiple actions on many different cell types. Fluticasone directly decreases inflammatory cells such as eosinophils, monocytes, mast cells, macrophages, and dendritic cells. It reduces the number of these cells and also the number of cytokines they produce.

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What are the systemic and local side effects of fluticasone?

Local side effects:
Sore throat, hoarse voice, opportunistic oral infections

Systemic side effects:
Growth retardation in children
Hyperglycaemia
Decreased bone mineral density
Immunosuppression
Effects on mood
(Many others)

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What has a greater affinity for the glucocorticoid receptor, cortisol or fluticasone?

fluticasone

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What is the predominant systemic delivery of fluticasone and why?

Oral bioavailability <1%. Therefore, any systemic delivery via the inhaled route is predominantly through the pulmonary vasculature.

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What is the drug target for mometasone?

Glucocorticoid receptor

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What is the mechanism of action for mometasone?

Very powerful drugs. Multiple actions on many different cell types. Mometasone directly decreases inflammatory cells such as eosinophils, monocytes, mast cells, macrophages, and dendritic cells. It reduces the number of these cells and also the number of cytokines they produce.

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What are the side effects of mometasone?

Local side effects:
Sore throat, hoarse voice, opportunistic oral infections

Systemic side effects:
Growth retardation in children
Hyperglycaemia
Decreased bone mineral density
Immunosuppression
Effects on mood
(Many others)

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What has a grater affinity for the glucocorticoid receptor, mometasone or cortisol? And what is the systemic delivery route for mometasone and why?

mometasone

Oral bioavailability <1%. Therefore, any systemic delivery via the inhaled route is predominantly through the pulmonary vasculature.

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What is the drug target for budesonide?

Glucocorticoid receptor

What is the mechanism of action for budesonide?

Very powerful drugs. Multiple actions on many different cell types. Budesonide directly decreases inflammatory cells such as eosinophils, monocytes, mast cells, macrophages, and dendritic cells. It reduces the number of these cells and also the number of cytokines they produce.

Why is it ok that budesonide is inhaled?

Oral bioavailability >10%. Therefore, inhaled budesonide will still result in some systemic absorption through the gastro-intestinal tract.

What is more potent, budesonide or mometasone?

budesonide is less potent than mometasone and fluticasone

What is the drug target for montelukast?

CysLT1 leukotriene receptor

What is the mechanism of action for montelukast?

Antagonism of CysLT1 leukotriene receptor on eosinophils, mast cells and airway smooth muscle cells decreases eosinophil migration, broncho-constriction and inflammation induced oedema

What are the side effects of montekulast?

Mild side effects:
Diarrhoea
Fever
Headaches
Nausea or vomiting

Serious side effects:
Mood changes
Anaphylaxis

When should montelukast be administered, before, after or during exercise?

For prophylaxis of exercise-induced bronchoconstriction, montelukast should be administered at least 2 hours before initiating exercise.

What symptom gives asthma away?

wheeze gives it away (suggests airways are contracting, causing turbulent breathing)(wheezing also due to hypersensitivity e.g., if allergy, it’s either responding to the wrong thing or responding too much)
asthma

What questions wouy=ld you ask someone who brought their child with asthma symptoms?

Is there a family history of asthma? How often do symptoms occur? Does coughing wake your child at night? Do the symptoms accompany a cold or are they unrelated to colds? How long do they last? Has your child needed emergency care for breathing difficulties? Does your child have any known pollen, dust, pet or food allergies? Is your child exposed to cigarette smoke or other airborne irritants?

What is the therapeutic objective for this patient?

Short term = Relief Relieve symptoms of breathlessness and expiratory wheeze during the acute asthma attack Long term = Prevention Dampen/prevent the late phase of the asthma attack Reduce the risk of further asthma attacks. Attempt to improve lung function KEY POINT: The management of asthma in children under 5 requires careful and relatively frequent monitoring. You can help minimize asthma symptoms by following a written asthma action plan you develop with the child's doctor to monitor symptoms and adjust treatment as necessary.

What is the difference and similarity between normal/ asthmatic/ medicated airways?

How can you give salbutamol to a patient in a hospital setting?

oxygen-driven nebuliser

What is the difference between oral and inhalation of aerosol salbutamol?

local vs systemic oral is a much higher dose

exhaled mucociliary clearance absorption from lungs oral swallowed some will be absorbed across the mucous membrane in the oral cavity and pharynx

What can you use to increase the function of the inhaler?

spacer

What is the vicious cycle of viral infection and asthma?

Common viral infections (e.g. rhinovirus) are known to release mediators that specifically activate eosinophils. Eosiniophils can induce epithelial damage (e.g. due to release of major basic protein). This increases susceptibility to viral infections. Vicious cycle

Like salbutamol, a significant proportion of inhaled fluticasone is actually swallowed. Despite this, the oral bioavailability (i.e. the proportion of drug that reaches the plasma VIA the gastrointestinal tract) is less than 1%. Why is this the case?

first pass inactivation

What is the mechanism of action for montelukast and why might it be particularly useful for NSAID (Non-steroidal anti-inflammatory drug)-induced asthma?