Montelukast is a leukotriene receptor antagonist (LTRA) used for the maintenance treatment of asthma and to relieve symptoms of seasonal allergies. It is usually administered orally. Montelukast blocks the action of leukotriene D4 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 locus of operation, it does not interact with other allergy medications such as theophylline. Montelukast is marketed in United States and many other countries by Merck & amp; Co. with the brand name Singulair. It is available as oral tablets, chewable tablets, and oral granules.
Montelukast blocks the action of leukotriene D4 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.
Mechanism of action of Montelukast
Montelukast selectively antagonizes leukotriene D4 (LTD4) at the cysteinyl leukotriene receptor, CysLT1, in the human airway. Montelukast inhibits the actions of LTD4 at the CysLT1 receptor, preventing airway edema, smooth muscle contraction, and enhanced secretion of thick, viscous mucus. Montelukast, like zafirlukast, is a leukotriene receptor antagonist used as an alternative to anti-inflammatory medications in the management and chronic treatment of asthma and exercise-induced bronchospasm (EIB). Unlike zafirlukast, montelukast does not inhibit CYP2C9 or CYP3A4 and is, therefore, not expected to affect the hepatic clearance of drugs metabolized by these enzymes.
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Montelukast inhibits bronchoconstriction due to antigen challenge. Montelukast is a selective leukotriene receptor antagonist of the cysteinyl leukotriene CysLT1 receptor. The cysteinyl leukotrienes (LTC4 , LTD4, LTE4) are products of arachidonic acid metabolism that are released from various cells, including mast cells and eosinophils. They bind to cysteinyl leukotriene receptors (CysLT) found in the human airway. Binding of cysteinyl leukotrienes to leukotriene receptors has been correlated with the pathophysiology of asthma, including airway edema, smooth muscle contraction, and altered cellular activity associated with the inflammatory process, factors that contribute to the signs and symptoms of asthma. Montelukast binding to the CysLT1, receptor is high-affinity and selective, preferring the CysLT1 receptor to other pharmacologically important airway receptors, such as the prostanoid, cholinergic, or beta-adrenergic receptor. Montelukast inhibits physiologic actions of LTD4 at the CysLT1 receptors, without any agonist activity.
Indications of Montelukast
- Asthma
- COPD
- Allergic rhinitis
- Asthma, maintenance
- Bronchospasm prophylaxis
- Asthma bronchial
- Exercise-induced bronchoconstriction
- Perennial allergic rhinitis
- Seasonal allergic rhinitis
- Prophylaxis and chronic treatment of asthma
- Relief of symptoms of seasonal allergic rhinitis and perennial allergic rhinitis
- Prevention of exercise-induced bronchoconstriction (EIB)
- Prevent the narrowing of airways triggered by exercise
- Seasonal allergic rhinitis (hay fever) symptoms.
Contra-Indications of Montelukast
- Increased Eosinophils in the Blood
- Having Thoughts of Suicide
- Depression
- Inflammation of Blood Vessels in the Skin
- anxiety disorder
Allergies to
- Montelukast
- Leukotriene Receptor Antagonist
Dosages of Montelukast
Strengths: 5 mg; 4 mg; 10 mg;
Adult dosage (ages 15 years and older)
- The typical dosage is one 10-mg tablet taken once daily in the evening.
Child dosage (ages 6–14 years)
- The typical dosage is one 5-mg chewable tablet taken once daily in the evening.
Child dosage (ages 2–5 years)
- The typical dosage is one 4-mg chewable tablet once daily in the evening.
Child dosage (ages 0–1 year)
- It has not been determined that the use of montelukast oral tablet is safe or effective for asthma in children younger than 12 months.
Allergic Rhinitis
- 10 mg orally once a day
Asthma – Maintenance
- 10 mg orally once a day
Bronchospasm Prophylaxis
- 10 mg orally once a day at least 2 hours before exercise
Pediatric Dose for Asthma
12 to 23 months
- One sachet of 4 mg oral granules once a day
2 to 5 years
- 4 mg chewable tablet or one sachet oral granules once a day
6 to 14 years
- 5 mg chewable tablet orally once a day
15 years or older
- 10 mg tablet orally once a day
Allergic Rhinitis
Seasonal Allergic Rhinitis
- Less than 2 years: Not approved.
2 to 5 years
- 4 mg chewable tablet or one sachet of 4 mg oral granules once a day
6 to 14 years
- 5 mg chewable tablet orally once a day
15 years or older
- 10 mg tablet orally once a day
Perennial Allergic Rhinitis
6 to 23 months
- One sachet of 4 mg oral granules once a day
2 to 5 years
- 4 mg chewable tablet orally once a day
6 to 14 years
- 5 mg chewable tablet orally once a day
15 years or older
- 10 mg tablet orally once a day
Bronchospasm Prophylaxis
- Less than 6 years: Not approved.
6 to 14 years
- 5 mg chewable tablet orally once a day
15 years or older
- 10 mg tablet orally once a day
Side Effects of Montelukast
The most common
- headache
- sore throat
- cough
- stomach pain
- Headache
- irritability
- restlessness
- sleeplessness
- unable to sleep
- stomach pain
- diarrhea
- dizziness, drowsiness
- upper respiratory tract infection.
- feeling unusually weak or tired
- upper respiratory tract infection.
Common
- agitation, including aggressive behaviour and/or hostility
- tremor
- irritability, restlessness, feeling anxious
- depression
- Abdominal or stomach pain
- stomach pain
- nausea, vomiting
- diarrhoea.
- agitation, including aggressive behaviour and/or hostility
- irritability, restlessness, feeling anxious
- depression
- seeing, feeling or hearing things that are not there (also called hallucinations)
- dream abnormalities, difficulty sleeping
- sleep walking.
- muscle aches or cramps, joint pain
- stomach pain
- nausea, vomiting
- diarrhoea.
Rare
- Agitation
- anxiety
- breathing problems
- confusion about identity, place, and time
- constipation
- fast, irregular, pounding, or racing heartbeat or pulse
- feeling sad or empty
- indigestion
- itching, puffiness, or swelling of the eyelids or around the eyes, face, lips, or tongue
- lack of appetite
- pains in the stomach, side, or abdomen, possibly moving to the back
- shaking or trembling of the hands or feet
Drug Interactions of Montelukast
Montelukast may interact with following drugs,supplement & may change the efficacy of drugs
- antiseizure medications (e.g., clobazam, phenobarbital, phenytoin, valproic acid, )
- aripiprazole
- “azole” antifungals (e.g., itraconazole, ketoconazole, voriconazole)
- baclofen
- barbiturates (e.g., butalbital, pentobarbital, phenobarbital)
- benzodiazepines (e.g., alprazolam, diazepam, lorazepam)
- Calcium channel blockers, diltiazem, verapamil
- domperidone
- famotidine
- carbamazepine
- carvedilol
- celecoxib
- ipratropium
- ketotifen
- levodopa
- macrolide antibiotics (e.g., azithromycin, clarithromycin, erythromycin)
- magnesium sulfate
- methylphenidate
- mirtazapine
- montelukast
- omeprazole
- quinolone antibiotics (e.g., levofloxacin, norfloxacin, moxifloxacin)
- selective serotonin reuptake inhibitors (SSRIs; e.g., paroxetine, fluoxetine, citalopram)
- serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
- sotalol
- tapentadol
- thiazide diuretics (water pills; e.g., hydrochlorothiazide, indapamide, )
- thioridazine
- tolterodine
- tramadol
- trimethoprim
- tricyclic antidepressants (e.g., amitriptyline, clomipramine, desipramine, trimipramine)
- “triptan” migraine medications (e.g., eletriptan, sumatriptan)
- tryptophan
- tyrosine kinase inhibitors (e.g., dasatinib, imatinib, nilotinib, sunitinib)
- theophylline
- trimethoprim
- warfarin
Pregnancy & Lactation Montelukast
FDA Pregnancy category B.
Pregnancy
Montelukast falls into category B. There are no well-done studies that have been done in humans with montelukast. But in animal studies, pregnant animals were given this medication, and the babies did not show any medical issues related to this medication.
Lactation
It is not known if montelukast passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
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