Montelukast

Indications

Montelukast is used for: Asthma, Allergic rhinitis, Exercise induced bronchospasm

Adult Dose

Oral Chronic asthma Adult: As film-coated tab: 10 mg once daily in the evening. Allergic rhinitis Adult: 10 mg once daily. Prophylaxis of exercise-induced asthma Adult: 10 mg at least 2 hr prior to exercise; do not take additional doses w/in 24 hr. Elderly: No dosage adjustment needed. Hepatic impairment: Mild to moderate: No dosage adjustment needed.

Child Dose

Asthma Prophylaxis and maintenance treatment in patients aged >12 months <12 months: Safety and efficacy not established 12-23 months: 4 mg (granules) PO once daily in evening 2-5 years: 4 mg (chewable tablet or granules) PO once daily in evening 6-14 years: 5 mg (chewable tablet) PO once daily in evening 15 years and older: 10 mg (conventional tablet) PO once daily in evening Exercise-Induced Bronchospasm Prophylaxis 6-15 years: 5 mg (chewable tablet) PO 2 hours before exercise; do not take additional dose within 24 hours >15 years: 10 mg PO 2 hours before exercise; do not take additional dose within 24 hours If taking drug for another indication, do not take additional dose to prevent EIB Perennial Allergic Rhinitis <6 months: Safety and efficacy not established 6-23 months: 4 mg (granules) PO once daily 2-5 years: 4 mg (chewable tablet or granules) PO once daily 6-14 years: 5 mg (chewable tablet) PO once daily 15 years and older: 10 mg (conventional tablet) PO once daily Seasonal Allergic Rhinitis <2 years: Safety and efficacy not established 2-5 years: 4 mg (chewable tablet) or 4 mg (granules) PO once daily 6-14 years: 5 mg (chewable tablet) PO once daily 15 years and older: 10 mg (conventional tablet) PO once daily

Renal Dose

Renal impairment: No dosage adjustment needed.

Administration

May be taken with or without food. For allergic rhinitis tablets can be taken once a day, morning or evening. For asthma, montelukast is recommended to be taken in the evening. For preventing exercise-induced bronchospasm montelukast needs to be two hours before exercise.

Contra Indications

Hypersensitivity.

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 mth. Lactation: Unknown whether agent is excreted in breast milk, use with caution

Pregnancy-Lactation

Pregnancy Available data from published prospective and retrospective cohort studies over decades in pregnant women have not established a drug-associated risk of major birth defects Animal data In animal reproduction studies, no adverse developmental effects were observed with oral administration to pregnant rats and rabbits during organogenesis at doses approximately 100 and 110 times, respectively, the maximum recommended human daily oral dose (MRHDOD) based on AUCs Poorly or moderately controlled asthma in pregnancy increases maternal risk of perinatal adverse outcomes such as preeclampsia and infant prematurity, low birth weight, and small for gestational age Lactation A published clinical lactation study reports presence of montelukast in human milk; data available on effects of drug on infants, either directly or through breast milk, do not suggest a significant risk of adverse events from exposure; effects of drug on milk production are unknown; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for therapy and any potential adverse effects on breastfed infant from treatment or from underlying maternal condition

Interactions

Induced hepatic metabolism resulting to decreased plasma concentration w/ potent inducers of cytochrome P450 isoenzymes (e.g. phenobarbital, phenytoin, rifampicin).

Adverse Effects

Side effects of Montelukast : >10% Headache (18.4%; similar to placebo) 1-10% >2% Abdominal pain, Eczema, Influenza, Laryngitis, Pharyngitis, Viral infection, Wheezing, Dental pain, Dizziness, Dyspepsia, Dental pain (2%), Dizziness (2%), Dyspepsia (2%)Elevated liver function tests (2%), Fever (2%), Gastroenteritis (2%), Nasal congestion (2%), Otitis (2%), Rash (2%), Urticaria (2%), >1% Bronchitis, Cough, Sinusitis, Upper respiratory tract infection <1% Allergic granulomatous angiitis (Churg-Strauss syndrome; rare), Cholestatic hepatitis (rare), Aggressive behavior, altered behavior, suicidal thoughts Potentially Fatal: Anaphylaxis, Churg-Strauss syndrome.

Mechanism of Action

Montelukast is a selective leukotriene receptor antagonist that blocks the effects of cysteinyl leukotrienes in the airways.