Leukotriene antagonist
Encyclopedia
A leukotriene antagonist (sometimes referred to as a leukast) is a drug that inhibits leukotriene
s, 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. They are less effective than corticosteroids and thus less preferred in the treatment of asthma.
block 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
.
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.
Leukotriene
Leukotrienes are fatty signaling molecules. They were first found in leukocytes . One of their roles is to trigger contractions in the smooth muscles lining the trachea; their overproduction is a major cause of inflammation in asthma and allergic rhinitis...
s, which are fatty compounds produced by the immune system that cause inflammation in asthma
Asthma
Asthma is the common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include wheezing, coughing, chest tightness, and shortness of breath...
and bronchitis
Bronchitis
Acute bronchitis is an inflammation of the large bronchi in the lungs that is usually caused by viruses or bacteria and may last several days or weeks. Characteristic symptoms include cough, sputum production, and shortness of breath and wheezing related to the obstruction of the inflamed airways...
, and constrict airways.
Leukotriene inhibitors (or modifiers), such as montelukast
Montelukast
Montelukast is a leukotriene receptor antagonist used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. It is usually administered orally...
, zafirlukast
Zafirlukast
Zafirlukast is an oral leukotriene receptor antagonist for the maintenance treatment of asthma, often used in conjunction with an inhaled steroid and/or long-acting bronchodilator. It is available as a tablet and is usually dosed twice daily. Another leukotriene receptor antagonist is montelukast...
and zileuton
Zileuton
Zileuton is an orally active inhibitor of 5-lipoxygenase, and thus inhibits leukotrienes formation. Zileuton is used for the maintenance treatment of asthma. Zileuton was introduced in 1996 by Abbott Laboratories and is now marketed in two formulations by Cornerstone Therapeutics Inc. under the...
, are used to treat those diseases. They are less effective than corticosteroids and thus less preferred in the treatment of asthma.
Inhibition of the 5-lipoxygenase pathway
Drugs such as zileutonZileuton
Zileuton is an orally active inhibitor of 5-lipoxygenase, and thus inhibits leukotrienes formation. Zileuton is used for the maintenance treatment of asthma. Zileuton was introduced in 1996 by Abbott Laboratories and is now marketed in two formulations by Cornerstone Therapeutics Inc. under the...
block 5-lipoxygenase, inhibiting the synthetic pathway of leukotriene metabolism, whereas drugs such as MK-886 block the 5-lipoxygenase activating protein
5-lipoxygenase activating protein
Arachidonate 5-lipoxygenase-activating protein also known as 5-lipoxygenase activating protein, or FLAP, is a protein that in humans is encoded by the ALOX5AP gene.- Function :...
(FLAP) and may help in treating atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...
.
Antagonism of cysteinyl-leukotriene type 1 receptors
Agents such as montelukastMontelukast
Montelukast is a leukotriene receptor antagonist used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. It is usually administered orally...
and zafirlukast
Zafirlukast
Zafirlukast is an oral leukotriene receptor antagonist for the maintenance treatment of asthma, often used in conjunction with an inhaled steroid and/or long-acting bronchodilator. It is available as a tablet and is usually dosed twice daily. Another leukotriene receptor antagonist is montelukast...
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
Bronchoalveolar lavage
Bronchoalveolar lavage is a medical procedure in which a bronchoscope is passed through the mouth or nose into the lungs and fluid is squirted into a small part of the lung and then recollected for examination. BAL is typically performed to diagnose lung disease...
fluid. This demonstrates that they have anti-inflammatory properties.