Leukotriene Antagonists

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Introduction

These are given in oral tablet form and are used to treat severe chronic asthma. They are only ever used in conjunction with corticosteroids.

Mechanism

  • They block the LTD4 receptor on smooth muscle, which normally responds to leukotriene activation. Thus by blocking this receptor they prevent bronchoconstriction.
  • Leukotrienes  are generally released by eosinophils and mast cells, and cause bronchoconstriction, oedema, and excess mucous constriction (basically things to do with inflammation). By blocking their receptors we can reduce these effects
  • They prevent both the early and late responses to an allergen.
  • They are also particularly useful in asprin induced asthma as well as being used in excersize induced asthma, and other moderate cases.
  • They are less effective than salbutamol and bronchodilation.

Drugs

  • Montelukastusually given once daily
  • Zafirlukast – generally given twice daily

Unwanted effects

These are generally rare, but can include:
  • Headache
  • Irritability
  • GI upset
  • Dry mouth / thirst
  • Oedema
  • Hypersensitivity reactions

Clinical use

Generally used in conjunction with corticosteroids and β2 agonists, when the latter are no longer providing effective relief.

References

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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

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