Systematic (IUPAC) name
(S,E)-2-(1-((1-(3-(2-(7-chloroquinolin-2-yl)vinyl)phenyl)-3-(2-(2-hydroxypropan-2-yl)phenyl)propylthio)methyl)cyclopropyl)acetic acid
Clinical data
Trade names Singulair
AHFS/ monograph
MedlinePlus a600014
Pregnancy cat. B (U.S.), B1 (Au)
Legal status Rx Only (U.S.), POM (UK), S4 (Au)
Routes Oral
Pharmacokinetic data
Bioavailability 63% to 73%
Protein binding 99%
Metabolism Hepatic (CYP3A4 and CYP2C9-mediated)
Half-life 2.7-5.5 hours
Excretion Biliary
CAS number 158966-92-8 YesY
ATC code R03DC03
PubChem CID 5281040
DrugBank APRD00434
ChemSpider 4444507 YesY
KEGG D08229 YesY
Chemical data
Formula C35H36ClNO3S 
Mol. mass 586.184 g/mol
SMILES eMolecules & PubChem
 N(what is this?)  (verify)

Montelukast (trade names Singulair and Montelo-10) is a leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies.[1][2] It is usually administered orally. Montelukast is a CysLT1 antagonist; that it blocks the action of leukotriene D4 (and secondary ligands LTC4 and LTE4) on the cysteinyl leukotriene receptor CysLT1 in the lungs and bronchial tubes by binding to it. This reduces the bronchoconstriction otherwise caused by the leukotriene and results in less inflammation.

Because of its method of operation, it is not useful for the treatment of acute asthma attacks. Again because of its very specific focus of operation, it does not interact with other asthma medications such as theophylline.

Another leukotriene receptor antagonist is zafirlukast (Accolate), taken twice daily. Zileuton (Zyflo), an asthma drug taken four times per day, blocks leukotriene synthesis by inhibiting 5-lipoxygenase, an enzyme of the eicosanoid synthesis pathway.

The Mont in Montelukast stands for Montreal, the place where Merck developed the drug.[3]


Medical uses

Montelukast is used for a number of conditions including: asthma, exercise induced bronchospasm, allergic rhinitis, and urticaria.[4] It is mainly used as a complementary therapy in adults in addition to inhaled corticosteroids, if they alone do not bring the desired effect. Corticosteroids reduce inflammation but have no effect on leukotrienes.

Adverse effects

Side effects include gastrointestinal disturbances, hypersensitivity reactions, sleep disorders and increased bleeding tendency, aside from many other generic adverse reactions. Its use is associated with a higher incidence of Churg–Strauss syndrome (whether or not this drug is 'unmasking' subclinical Churg–Strauss is as yet uncertain).

FDA Investigation

In March, 2008 the FDA announced that it would investigate whether mood changes and suicidal thoughts are possible side effects of drugs in this class, including the popular drug Singulair, which currently lists these side effects.[5]

On June 12, 2009 the Food and Drug Administration concluded their review into the possibility of neuropsychiatric side effects with leukotriene modulator drugs. Although clinical trials only revealed an increased risk of insomnia, post-marketing surveillance showed that the drugs are associated with a possible increase in suicidal behavior and other side effects such as agitation, aggression, anxiousness, dream abnormalities and hallucinations, depression, irritability, restlessness and tremor.[6]

Use with loratadine

Schering-Plough and Merck have sought permission to market a combined tablet with loratadine (Claritin) and montelukast (Singulair), as many patients combine the two themselves. However, the FDA has found no benefit from a combined pill for seasonal allergies over taking the two drugs in combination,[7] and on April 25, 2008, issued a "not approvable" letter for the combination.[8]


Singulair is covered by U.S. Patent No. 5,565,473[9] which is set to expire (by pediatric extension) on August 3, 2012.[10]

On May 28, 2009, the U.S. Patent and Trademark Office announced their decision to launch a reexamination of the patent covering Singulair. The decision to reexamine was driven by the discovery of references that were not included in the original patent application process. The references were submitted through Article One Partners, an online research community focused on finding literature relating to existing patents. The references included a scientific article produced by a Merck employee around the key ingredient of Singulair, and a previously filed patent in the same technology area.[11]

On December 17, 2009, the U.S. Patent and Trademark Office determined that the patent in question was valid based on the initial reexamination and new information provided.[12]


External links

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Look at other dictionaries:

  • Montelukast — Nombre (IUPAC) sistemático Ácido 2 [1 [[(1R) 1 [3 [2 (7 cloroquinolin 2 yl)etenil] fenil] 3 [2 (2 hidroxipropan 2 yl)fenil]propil] sulfanilmetil]ciclopropi …   Wikipedia Español

  • Montélukast — Général No CAS …   Wikipédia en Français

  • Montelukast — Strukturformel Allgemeines Freiname Montelukast Andere Namen …   Deutsch Wikipedia

  • montelukast — mon·te·lu·kast (mŏn tə lo͞oʹkăst) n. A drug that reduces the inflammatory response by acting as a leukotriene receptor antagonist, and is used to treat the signs and symptoms of asthma.   [monte , of unknown origin + lukast, leukotriene receptor… …   Universalium

  • montelukast — mon·te·lu·kast .mänt ə lü .kast n a leukotriene antagonist administered in the form of its sodium salt C35H35ClNNaO3S in tablet form to treat asthma or to relieve the symptoms of seasonal allergic rhinitis see singulair * * * n. see leukotriene… …   Medical dictionary

  • montelukast — n.; see leukotriene receptor antagonist …   The new mediacal dictionary

  • montelukast sodium — A competitive and selective Cys LT1 receptor antagonist that acts as a blocker of leukotrienes, which are potent endogenous bronchoconstrictors. A prophylactic; not useful to treat an ongoing attack of asthma. * * * mon·te·lu·kast so·di·um… …   Medical dictionary

  • MONT — montelukast …   Medical dictionary

  • MONT — • montelukast …   Dictionary of medical acronyms & abbreviations

  • 158966-92-8 — Montélukast Montélukast Général No CAS …   Wikipédia en Français

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