Dosing and uses of Singulair (montelukast)
Adult dosage forms and strengths
tablet
- 10mg
tablet, chewable
- 4mg
- 5mg
oral granules
- 4mg/packet
Asthma
Prophylaxis and maintenance treatment
10 mg (single 10-mg tablet) PO once daily in evening
Exercise-Induced Bronchospasm
Prophylaxis
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 exercise-induced bronchospasm (EIB)
Allergic or Perennial Rhinitis
10 mg (single 10-mg tablet) PO once daily
Administration
Patients aged ≥12 years with both asthma and allergic rhinitis: 1 dose PO at bedtime
Patients with allergic rhinitis: Dosing time may be individualized to patient needs
Granules may be taken directly; mixed in applesauce, carrots, rice, or ice cream; or dissolved in 5 mL of breast milk or baby formula (administer within 15 minutes of opening)
Pediatric dosage forms and strengths
tablet
- 10mg
tablet, chewable
- 4mg
- 5mg
oral granules
- 4mg/packet
Asthma
Prophylaxis and maintenance treatment in patients aged ≥12 months
<12 months: Safety and efficacy not established
12-24 months: 4 mg (granules) PO once daily in evening
2-6 years: 4 mg (chewable tablet or granules) PO once daily in evening
6-15 years: 5 mg (chewable tablet) PO once daily in evening
>15 years: 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
6-24 months: 4 mg (granules) PO once daily
2-6 years: 4 mg (chewable tablet or granules) PO once daily
6-15 years: 5 mg (chewable tablet) PO once daily
>15 years: 10 mg (conventional tablet) PO once daily
Seasonal Allergic Rhinitis
<2 years: Safety and efficacy not established
2-6 years: 5 mg (chewable tablet) or 4 mg (granules) PO once daily
6-15 years: 5 mg (chewable tablet) PO once daily
>15 years: 10 mg (conventional tablet) PO once daily
Singulair (montelukast) adverse (side) effects
Some adverse drug reactions vary by age group
>10%
Headache (18.4%; similar to placebo)
1-10%
Abdominal pain (≥2%)
Eczema (≥2%)
Influenza (≥2%)
Laryngitis (≥2%)
Pharyngitis (≥2%)
Viral infection (≥2%)
Wheezing (≥2%)
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%)
Bronchitis (≥1%)
Cough (≥1%)
Sinusitis (≥1%)
Upper respiratory tract infection (≥1%)
<1%
Allergic granulomatous angiitis (Churg-Strauss syndrome; rare)
Cholestatic hepatitis (rare)
Aggressive behavior, altered behavior, suicidal thoughts
Postmarketing Reports
Hematologic: Increased bleeding tendency, thrombocytopenia
Immunologic: Hypersensitivity reactions (eg, anaphylaxis, hepatic eosinophilic infiltration)
Psychiatric: Agitation, including aggressive behavior or hostility, anxiousness, depression, disorientation, dream abnormalities, hallucinations, insomnia, irritability, restlessness, somnambulism, suicidal thinking and behavior (including suicide), tremor
Neurologic: Drowsiness, paresthesia or hypesthesia, seizures
Cardiac: Palpitations
Respiratory, thoracic, mediastinal: Epistaxis, pulmonary eosinophilia
Gastrointestinal: Diarrhea, dyspepsia, nausea, pancreatitis, vomiting
Hepatobiliary: Cases of cholestatic hepatitis, hepatocellular liver injury, and mixed-pattern liver injury have been reported, mostly occurring in combination with other confounding factors (eg, use of other medications, administration to patients who had underlying potential for liver disease [eg, alcohol use or other forms of hepatitis])
Dermatologic: Angioedema, bruising, erythema multiforme, erythema nodosum, pruritus, urticaria
Musculoskeletal: Arthralgia, myalgia (including muscle cramps)
General: Edema
Warnings
Contraindications
Hypersensitivity
Cautions
Not to be given for acute asthma attacks, including status asthmaticus
Advise patients to have appropriate rescue medication available
Inhaled corticosteroid may be reduced gradually; do not abruptly substitute montelukast for inhaled or oral corticosteroids
Patients with known aspirin sensitivity should continue to avoid aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) while taking montelukast; not to be given for treatment of bronchoconstriction resulting from aspirin or NSAID intake
Neuropsychiatric events (eg, abnormal dreams, agitation) reported
Systemic eosinophilia reported, sometimes presenting with clinical features of vasculitis consistent with Churg-Strauss syndrome; these events are usually (but not always) associated with tapering of PO corticosteroid therapy
Use with caution in phenylketonuria; 4-mg and 5-mg chewable tablets contain phenylalanine
Pregnancy and lactation
Pregnancy category: B
Lactation: Unknown whether agent is excreted in breast milk, use with caution
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Singulair (montelukast)
Mechanism of action
Blocks binding of leukotriene D4 to its receptor; alters pathophysiology associated with inflammatory process that contributes to signs and symptoms of asthma
Absorption
Bioavailability: 64% (mean)
Peak plasma time: Tablet, 3-4 hr; chewable tablet, 2-2.5 hr; granules, 1-3 hr
Distribution
Protein bound: >99%
Vd: 8-11 L
Metabolism
Metabolized by CYP3A4 and CYP2C9
Elimination
Half-life: 2.7-5.5 hr
Clearance: 45 mL/min
Excretion: Feces (86%), urine (0.2%)
