Montelukast information from DrugsUpdate
P - Caution when used during pregnancy
L - Caution when used during lactation
FI - Food *
Montelukast (trade name Singulair)(Openair in Pakistan) 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 is a CysLT1 antagonist; that is it 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 focus of operation, it does not interact with other allergy 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.
Pharmacodynamics
Pharmacokinetics
Montelukast is a selective leukotriene receptor antagonist that blocks the effects of cysteinyl leukotrienes in the airways.
Absorption
Rapidly absorbed from the GI tract (oral). Peak plasma concentrations in 2-4 hours. Mean oral bioavailability: 64%.
Distribution
Protein-binding: >99%.
Metabolism
Extensively hepatic by CYP3A4, CYP2A6 and CYP2C9 isoenzymes.
Excretion
Principally via faeces; elimination half-life prolonged in mild to moderate hepatic impairment.
Montelukast Indications / Montelukast Uses
Information Not Available
Montelukast Adverse Reactions / Montelukast Side Effects
Dizziness, fatigue, fever; rash; abdominal pain, dyspepsia, dental pain, gastroenteritis; increased AST; weakness; cough, nasal congestion. Aggression, agitation, angioedema, arthralgia, bleeding tendency, bruising, cholestasis, diarrhoea, dream abnormalities, drowsiness, oedema, eosinophilia, hallucinations, hepatic eosinophilic infiltration (rare), hepatitis, hypersensitivity, hypoaesthesia, insomnia, irritability, muscle cramps, myalgia, nausea, palpitation, pancreatitis, paraesthesia, pruritus, restlessness, seizure, urticaria, vasculitis, vomiting.
Potentially Fatal: Anaphylaxis, Churg-Strauss syndrome.
Precautions
Information Not Available
Special Precautions
Not for the relief of acute bronchospasm. Not to be used as monotherapy for the prevention of exercise-induced bronchospasm. Patients in whom asthma is precipitated by aspirin or other NSAIDs should continue to avoid aspirin and NSAIDs. Do not abruptly substitute for oral or inhaled corticosteroids. Be alert for any signs of Churg-Strauss syndrome. Pregnancy and lactation. Children <6 months.
Other Drug Interactions
Metabolism may be increased with rifampicin, phenobarbital, phenytoin. Peripheral oedema may occur with prednisone.
Other Interactions
Food Interaction
Serum levels may be reduced with St John's wort.
Dosage
Oral
Chronic asthma
Adult: 10 mg once daily in the evening.
Child: 2-5 years: 4 mg daily; 6-14 years: 5 mg daily; ≥15 years: 10 mg once daily. All doses to be taken in the evening.
Oral
Allergic rhinitis
Adult: 10 mg once daily in the evening.
Oral
Prophylaxis of exercise-induced asthma
Adult: 10 mg at least 2 hr prior to exercise; do not admin additional doses within 24 hours.
Child: ≥15 years: 10 mg at least 2 hours prior to exercise; do not admin additional doses within 24 hours.
Food(before/after)
Information Not Available
List of Contraindications
Montelukast and Pregnancy
Caution when used during pregnancy
Montelukast and Lactation
Caution when used during lactation
Montelukast and Children
Safety and efficacy not established for treatment of asthma in patients younger than 12 months of age. Safety and efficacy not established for treatment of allergic rhinitis in patients younger than 2 years of age. Safety and efficacy not established for treatment of perennial allergic rhinitis in patients younger than 6 months of age. Safety and efficacy not established for treatment of EIB in patients younger than 15 years of age.
Montelukast and Geriatic
Information Not Available
Montelukast and Other Contraindications
Information Not Available
Storage
Oral
Store at 15-30°C (59-86°F). Protect from moisture and light.
Lab interference
Oral
Store at 15-30°C (59-86°F). Protect from moisture and light.
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