Asthma Drugs Flashcards Preview

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Flashcards in Asthma Drugs Deck (12)
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1
Q

Aims of asthma treatment

A

Decrease inflammation
Prevent bronchoconstruction
Restore airway calibre to normal

2
Q

Atopic and non-atopic triggers

A

Non atopic: exercise; resporatory infection, pollutants (intrinsic)
Atopic: pollen, dust, animal fur (allergic) - trigger B cell production = inflamm, bronchoconstriction

3
Q

Phases of asthma attack

A
Immediate/early- 
= bronchodilator
- bronchospasm, mast cells release spasmogens - histamine, prostaglandins 
- mast cells release inflammatory mediators - interleukins, macrophage inflam protein, tumor necrosis factor, chemotaxins and chemokines attract WBC
Late phase -
- anti-inflammatory
- progressing inflam reaction
- lymphocytes and eosinophils invade
- release cytokines, chemokines
- hyperplasia
4
Q

Beta-2 adrenergic receptor antagonists

- bronchodilator

A

direct action on B2 adreno-receptors on bronchiole smooth muscle causing them to relax and dilate
inhibit mediator release from mast cells
act on cilia to increase mucus clearance
short acting = Salbutamol, Terbutaline, last 4-6 hours, use when needed
longer acting = Salmeterol, last 12 hours
given by inhalation to minimize tremor
tolerance can develop, overcome by glucocorticoids

5
Q

Theophylline

- bronchodilator

A

Eg. Xanthine
- PDE inhibitor
- used with steroids when asthma response to B2 agonist inadequate
- can be given i.v in acute severe asthma
SE = stimulant: tremor, sleep disturbance, stimulate heart, vasodilation, anorexia, nausea and vomiting

6
Q

Muscarinic receptor antagonists

- bronchodilator

A

Eg. Ipratropium

  • max affects 30 mins, last 3-5 hours
  • poorly absorbed in systemic circulation
  • inhibits elevated mucus secretion and increase clearance of secretions
  • blocks action of endogenous acetylcholine at muscarinic receptors
7
Q

Leukotriene receptor antagonists

- bronchodilator

A

Eg. Monteleukast (x 1 daily), Zafirlukast (x 2 daily)
- given orally
- prevents exercise-induced and aspirin-sensitive asthma
- action additive with B2 agonists
- main use is add on for uncontrolled mild/moderate asthma
- act at cysteinyl-leukotriene receptors
on bronchiole smooth muscle cells
- prevent actions of leukotrienes which are:
> bronchial spasmogens
> stimulate mucus secretion
SE= headache, GI effects

8
Q

Glucocorticoids

- anti-inflammatory

A

Eg. Beclometasone diproprionate, Budesonide, Fluticasone propionate, Prednislone/Hydrocortisone

  • given by inhalation
  • full effects may take days to develop
  • decrease production of cytokines, spasmogens, leukocyte chemotaxins to decrease bronchospasm = decrease inflammatory cells
9
Q

Mechanism of action of glucocorticoids

A
  1. enter cells and binds to receptors in cytoplasm
  2. receptor complex moves to nucleus
  3. binds to DNA in nucleus
  4. alters gene transcription - repression of interleukin 3
10
Q

Clinical use of glucocorticoids

A

to help control attacks
give inhaled steroid with additional agent for severe asthma eg Budesonide + B2 agonist
iv hydrocortisone and oral prednisolone for acute exacerbation
short course oral prednisolone for deterioration’s
SE = oropharyngeal thursh, dysphoria (difficulty speaking) - minimised by use of spacer
oral/regular large doses = adrenal suppression

11
Q

Cromoglicate

A

Eg. Nedocromil Sodium
- can decrease both early and late phase responses
- decreases bronchial hyper-reactivity
- effective in asthma caused by antigen, exercise, irritants
- unpredictable response - children respond better
mechanisms:
decrease neuronal reflexes
inhibit release of T cell cytokines
affects inflammatory cells and mediators
SE = irritation of upper respiratory tract, hypersensitivity reactions
inhalation

12
Q

Biological agents

A

Eg Omalizumab
- recombinant DNA-derived humanized IgG1 monoclonal antibody
- subcutaneous injection every 2-3 weeks = absorbed slowly
mechanisms:
binds to human IhE
inhibits binding of IgE to IgE receptor on surface of mast cells and basophils
inhibits IgE mediated cascade of asthma causing inflammation and bronchoconstriction
SE = anaphylaxis, malignancies