Montelukast Should Not Be Taken Twice Daily
Montelukast is specifically formulated and FDA-approved for once-daily dosing only, and taking it twice daily is not recommended or supported by evidence. 1
FDA-Approved Dosing
The FDA label explicitly states that montelukast should be administered once daily, with specific dosing based on age 1:
- Adults and adolescents ≥15 years: 10 mg once daily
- Children 6-14 years: 5 mg once daily
- Children 2-5 years: 4 mg once daily
- Infants 6-23 months: 4 mg once daily
For asthma, the medication should be taken in the evening or at bedtime. 2, 3 For exercise-induced bronchoconstriction, it should be taken at least 2 hours before exercise, but an additional dose should not be taken within 24 hours of a previous dose. 1
Why Once-Daily Dosing Is Sufficient
Montelukast has a pharmacokinetic profile that supports 24-hour efficacy with a single daily dose. 4 The medication:
- Begins working within 1-2 hours of administration 4
- Maintains bronchoprotective effects for 24 hours 4
- Does not develop tolerance with long-term use 4
- Exhibits a flat dose-response curve, meaning higher doses do not produce greater efficacy 5
Clinical Evidence Supporting Once-Daily Dosing
All major asthma and rhinitis guidelines consistently recommend once-daily dosing. The NAEPP guidelines state that "montelukast is taken once daily, whereas zafirlukast is used twice daily," clearly distinguishing the dosing schedules of different leukotriene receptor antagonists. 5
Studies in chronic rhinosinusitis with nasal polyps used montelukast 10 mg once daily and demonstrated significant symptom improvement, with total symptom scores improving from 5.9 to 1.75 over 6 weeks. 5
Safety Concerns with Altered Dosing
The FDA has issued a black box warning for serious neuropsychiatric events including suicidal thoughts or actions with montelukast. 2, 3 Taking twice the recommended dose could potentially:
- Increase the risk of neuropsychiatric adverse effects
- Not provide additional therapeutic benefit due to the flat dose-response curve 5
- Expose patients to unnecessary medication without proven efficacy
Common Pitfall to Avoid
If asthma or allergic rhinitis symptoms are not adequately controlled on once-daily montelukast, the solution is not to increase the frequency of dosing. 5 Instead:
- Verify medication adherence and proper timing of administration 5
- Consider that inhaled corticosteroids are superior to montelukast as first-line therapy for mild to moderate persistent asthma 3
- Add inhaled corticosteroids if not already prescribed, as montelukast should not be used as monotherapy for persistent asthma 5
- Evaluate for alternative diagnoses if no benefit is seen within 4-6 weeks 4
For patients with both asthma and allergic rhinitis, only one tablet daily should be taken in the evening—not separate doses for each condition. 1