Montelukast

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Montelukast
Montelukast2DCSD.svg
Montelukast 3D ball-and-stick.png
Systematic (IUPAC) name
(R,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/Drugs.com monograph
MedlinePlus a600014
Pregnancy
category
  • AU: B1
  • US: B (No risk in non-human studies)
Legal status
Routes of
administration
Oral
Pharmacokinetic data
Bioavailability 63% to 73%
Protein binding 99%
Metabolism Hepatic (CYP3A4 and CYP2C9-mediated)
Biological half-life 2.7-5.5 hours
Excretion Biliary
Identifiers
CAS Number 158966-92-8 YesY
ATC code R03DC03 (WHO)
PubChem CID: 5281040
IUPHAR/BPS 3340
DrugBank DB00471 YesY
ChemSpider 4444507 YesY
UNII MHM278SD3E YesY
KEGG D08229 YesY
ChEBI CHEBI:50730 YesY
ChEMBL CHEMBL787 YesY
Chemical data
Formula C35H36ClNO3S
Molecular mass 586.184 g/mol
  • O=C(O)CC1(CC1)CS[C@@H](c2cccc(c2)\C=C\c3nc4cc(Cl)ccc4cc3)CCc5ccccc5C(O)(C)C
  • InChI=1S/C35H36ClNO3S/c1-34(2,40)30-9-4-3-7-25(30)13-17-32(41-23-35(18-19-35)22-33(38)39)27-8-5-6-24(20-27)10-15-29-16-12-26-11-14-28(36)21-31(26)37-29/h3-12,14-16,20-21,32,40H,13,17-19,22-23H2,1-2H3,(H,38,39)/b15-10+/t32-/m1/s1 YesY
  • Key:UCHDWCPVSPXUMX-TZIWLTJVSA-N YesY
  (verify)

Montelukast (trade name Singulair) is a leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies.[1][2] Montelukast comes as a tablet, a chewable tablet, flash tablet and granules to take by mouth.[3] Montelukast is usually taken once a day with or without food.[3] Montelukast is a CysLT1 antagonist; 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 mechanism of action, it does not interact with other asthma medications such as theophylline.

Another leukotriene receptor antagonist is zafirlukast (Accolate). Zileuton (Zyflo), an asthma drug, 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.[4]

Medical uses

Montelukast is used for a number of conditions including asthma, exercise induced bronchospasm, allergic rhinitis, primary dysmenorrhoea and urticaria.[5] It is mainly used as a complementary therapy in adults in addition to inhaled corticosteroids, if they alone do not bring the desired effect. It is also used to prevent allergic reactions and asthma flare-ups during the administration of intravenous immunoglobulin.

Montelukast is administered as montelukast sodium, with 5.2 mg of montelukast sodium being equivalent to 5 mg of montelukast.[6]

Adverse effects

Side effects include gastrointestinal disturbances, headaches and, hypersensitivity reactions, in addition to other generic adverse reactions. Drowsiness is also a common side effect.

FDA investigation

In March 2008, the U.S. Food and Drug Administration (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.[7]

On June 12, 2009, the FDA 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.[8]

Use with loratadine

Schering-Plough and Merck 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,[9] and on April 25, 2008, issued a "not approvable" letter for the combination.[10]

Uses under study

Ludwig Aigner from Paracelsus Medical University in Austria presented findings at the October 2015 meeting of the Society for Neuroscience in Chicago which showed that administration of Montelukast to older rats rejuvenated their brains, returning the same functionality as that of young rats. Human trials are planned, starting with Parkinsons patients.[11] The researchers conducted the experiment with montelukast because it reduces inflammation in the lungs and they thought it might also reduce inflammation in the brain. Some research has suggested that decline in memory skills may be associated with inflammation in the brain.[12]

Dosage and administration

The usual dose of Montelukast in adults and teenagers is one 10 mg tablet taken orally a day. In children 6 to 14 years of age the usual dosage is one 5 mg chewable tablet a day.

Patents

Singulair was covered by U.S. Patent No. 5,565,473[13] which expired on August 3, 2012.[14] The same day, the FDA approved several generic versions of montelukast.[15]

The United States Patent and Trademark Office launched a reexamination of the patent covering Singulair on May 28, 2009. The decision 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 on the active ingredient in Singulair. A previously filed patent had been submitted in the same technology area.[16] Seven months later the U.S. Patent and Trademark Office determined that the patent in question was valid based on the initial reexamination and new information provided, submitting their decision on December 17, 2009.[17]

Brand names

Montelukast is sold under a variety of brand names including Montelo-10, Monteflo, and Lukotas in India, Montril, Lumona, Lumenta, and Arokast in Bangladesh and Respicare in Pakistan.

References

  1. Lipkowitz, Myron A. and Navarra, Tova (2001) The Encyclopedia of Allergies (2nd ed.) Facts on File, New York, p. 178, ISBN 0-8160-4404-X
  2. "Asthma / Allergy ". Mascothealth.com. Retrieved 9 April 2011.
  3. 3.0 3.1 Montelukast article on Medline Plus http://www.nlm.nih.gov/medlineplus/druginfo/meds/a600014.html "Montelukast comes as a tablet, a chewable tablet, and granules to take by mouth. Montelukast is usually taken once a day with or without food."
  4. http://www.merckfrosst.ca/mfcl/en/corporate/research/accomplishments/singulair.html
  5. Lua error in package.lua at line 80: module 'strict' not found.
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  7. FDA Investigates Merck Drug-Suicide Link
  8. Updated Information on Leukotriene Inhibitors: Montelukast (marketed as Singulair), Zafirlukast (marketed as Accolate), and Zileuton (marketed as Zyflo and Zyflo CR). Food and Drug Administration. Published June 12, 2009. Accessed June 13, 2009.
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  10. Schering-Plough press release - Schering-Plough/MERCK Pharmaceuticals Receives Not-Approvable Letter from FDA for Loratadine/Montelukast
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  13. 5,565,473
  14. Singular patent details
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External links