When Does Singulair (Montelukast) Reach Therapeutic Levels?
Montelukast begins producing clinical benefits within 1 day of starting therapy, with onset of action occurring by the second day of daily treatment. 1
Onset of Therapeutic Effect
Clinical improvements are evident within 24 hours of initiating montelukast therapy in children aged 2 to 14 years with persistent asthma, as demonstrated by improvements in lung function and reductions in as-needed beta-agonist usage 2, 3
The onset of action occurs by the second day of daily treatment for allergic rhinitis symptoms 1
After oral administration of 10 mg in adults, plasma concentrations remain above effective therapeutic levels for at least 24 hours, supporting the once-daily dosing regimen 4
Pharmacokinetic Profile
Montelukast demonstrates a long elimination half-life that supports once-daily dosing and maintains therapeutic drug levels throughout the 24-hour dosing interval 5
The medication can be taken without regard to meals, though administration with meals may improve gastrointestinal tolerability 6
Evening or bedtime administration is recommended based on the drug's pharmacodynamic profile, particularly for asthma management 6, 7
Clinical Implications
The rapid onset within 1 day makes montelukast suitable for relatively quick symptom control, though it is not intended for acute bronchospasm relief 2, 3
Sustained therapeutic effects persist during extended treatment without evidence of tachyphylaxis after up to 140 weeks in adults and 80 weeks in pediatric patients 3
For children aged 2-5 years with persistent asthma, the clinical benefit was evident within 1 day of starting the 4 mg chewable tablet formulation 3
Important Caveats
While therapeutic levels are reached quickly, montelukast is less effective than intranasal corticosteroids for allergic rhinitis and should not be considered first-line therapy when intranasal steroids are appropriate 1
The FDA black box warning regarding neuropsychiatric events necessitates monitoring for unusual behavioral or mood changes when starting montelukast, despite its rapid therapeutic onset 1, 6, 5
Montelukast provides continuous control rather than acute symptom relief, distinguishing it from rescue medications like short-acting beta-agonists 5