What is the recommended dosing regimen for montelukast (Singulair) in an 11-month-old child?

Montelukast Dosing for an 11-Month-Old

For an 11-month-old infant, prescribe montelukast 4 mg oral granules once daily in the evening, as this is the FDA-approved dose for infants 6 to 23 months of age. 1

Critical Safety Warning Before Prescribing

You must explicitly counsel parents about the FDA black box warning regarding serious neuropsychiatric events, including suicidal thoughts, depression, anxiety, sleep disturbances, and behavioral changes, before prescribing montelukast to any child. 2 Safer alternatives, particularly inhaled corticosteroids, should be discussed and considered first. 2

• Monitor closely for unusual behavioral or mood changes, particularly during the first weeks of therapy. 2
• Parents should be instructed to discontinue the medication immediately and contact you if any concerning behavioral changes occur. 2

Specific Dosing Instructions

Dose and Formulation

• Administer one 4-mg packet of oral granules once daily. 1
• The oral granule formulation is specifically designed for infants and young children who cannot chew tablets. 1

Administration Methods

The FDA provides several validated administration options 1:

• Direct administration: Pour granules directly into the infant's mouth
• Mixed with breast milk or formula: Dissolve in 1 teaspoonful (5 mL) of cold or room-temperature breast milk or formula
• Mixed with food: Combine with a spoonful of cold or room-temperature soft food (only applesauce, carrots, rice, or ice cream based on stability studies) 1

Critical Administration Rules

• Do not open the packet until ready to use. 1
• Administer the full dose within 15 minutes of opening the packet. 1
• Never store mixed granules for future use—discard any unused portion. 1
• Do not dissolve in liquids other than breast milk or formula, though other liquids may be given after administration. 1
• Can be given without regard to meals. 1

Clinical Context and Positioning

When to Use Montelukast in This Age Group

• Montelukast is FDA-approved for asthma in infants ≥12 months and for perennial allergic rhinitis in infants ≥6 months. 1 At 11 months, this patient falls within the approved age range for allergic rhinitis but just below the asthma indication.
• Consider montelukast as an alternative therapy for mild persistent asthma when inhaled corticosteroids cannot be used or compliance is problematic. 3 The once-daily oral administration offers superior compliance compared to inhaled therapies. 4

Pharmacokinetic Considerations

• Infants 6-11 months have 60% higher systemic exposure (AUC) and 89% higher peak concentrations (Cmax) compared to adults, with greater variability in plasma levels. 1
• Despite higher exposure, the 4-mg dose has demonstrated acceptable safety and tolerability in this age group. 1
• The plasma half-life ranges from 2.7 to 5.5 hours, with minimal drug accumulation during once-daily dosing. 1

Common Adverse Events

In infants 6-23 months, common adverse events (≥2% frequency, more than placebo) include: 2

• Upper respiratory infection
• Wheezing
• Otitis media
• Pharyngitis
• Tonsillitis
• Cough
• Rhinitis

The overall frequency of adverse events in montelukast-treated children is comparable to placebo. 4, 5

Important Clinical Pitfalls

• Do not use montelukast for acute asthma exacerbations or rescue therapy—ensure parents have a short-acting beta-agonist available for acute symptoms. 3
• Evening administration is recommended based on pharmacodynamic profile, though timing can be individualized for allergic rhinitis. 1
• No dose adjustment is needed for renal insufficiency, as montelukast is excreted via bile, not urine. 1
• Clinical benefit typically appears within 1 day of starting therapy. 4, 5