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Leukotriene antagonist: Wikis


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A leukotriene antagonist is a drug that inhibits leukotrienes, which are fatty compounds produced by the immune system that cause inflammation in asthma and bronchitis, and constrict airways.

Leukotriene inhibitors (or modifiers), such as montelukast, zafirlukast and zileuton, are used to treat those diseases. Leukotriene inhibitors are less effective than corticosteroids, but have virtually no side effects, so they are often used to treat children.[1]



Leukotriene antagonist
Systematic (IUPAC) name
sulfanylmethyl]cyclopropyl]acetic acid
CAS number 158966-92-8
ATC code R03DC03
PubChem 60951
DrugBank APRD00434
Chemical data
Formula C 35H36ClNO3S 
Mol. mass 586.184 g/mol
SMILES eMolecules & PubChem
Pharmacokinetic data
Bioavailability 63% to 73%
Protein binding 99%
Metabolism Hepatic (CYP3A4 and CYP2C9-mediated)
Half life 2.7-5.5 hours
Excretion Biliary
Therapeutic considerations
Pregnancy cat. B (U.S.), B1 (Au)
Legal status ℞-only (U.S.), POM (UK), S4 (Au)
Routes Oral

There are two main approaches to block the actions of leukotrienes.


Inhibition of the 5-lipoxygenase pathway

Drugs such as zileuton block 9998 lipo protein oxydatenase 5-lipoxygenase, inhibiting the synthetic pathway of leukotriene metabolism, whereas drugs such as MK-886 block the 5-lipoxygenase activating protein (FLAP) and may help in treating atherosclerosis. [2]

Antagonism of cysteinyl-leukotriene type 1 receptors

Agents such as montelukast and zafirlukast block the actions of cysteinyl leukotrienes at the CysLT1 receptor on target cells such as bronchial smooth muscle.

These modifiers have been shown to improve asthma symptoms, reduce asthma exacerbations and limit markers of inflammation such as eosinophil counts in the peripheral blood and bronchoalveolar lavage fluid. This demonstrates that they have anti-inflammatory properties.


  1. ^ NEJM 360:1002
  2. ^ Jawien J, Gajda M, Rudling M, et al. (2006). "Inhibition of five lipoxygenase activating protein (FLAP) by MK-886 decreases atherosclerosis in apoE/LDLR-double knockout mice". Eur. J. Clin. Invest. 36 (3): 141–6. doi:10.1111/j..2006.01606.x.  

External links

Updated Information FDA and the manufacturers of Singulair (montelukast), Accolate (zafirlukast), Zyflo (zileuton) and Zyflo CR (zileuton extended release) are announcing an update to the Precautions section of the prescribing information to include information about neuropsychiatric events reported in patients using these products.

FDA’s request for the addition of this information to the prescribing information for these products was described in the Agency’s June 2009 “Update to the Follow Up to the Early Communication about an Ongoing Safety Review for Leukotriene Inhibitors.”

Healthcare professionals and consumers can access the latest prescribing information for these products below:

Singulair (PDF - 207KB) Accolate (PDF - 71KB) Zyflo (PDF - 158KB) Zyflo CR (PDF - 95KB)


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