Can You Take Singulair and Zyrtec Together?
Yes, you can safely take montelukast (Singulair) and cetirizine (Zyrtec) together—this combination is both safe and more effective than either medication alone for treating allergic rhinitis. 1, 2, 3
Evidence Supporting Combination Therapy
Safety Profile
- No contraindications or drug interactions exist between montelukast and antihistamines like cetirizine. Clinical guidelines do not list any precautions for concurrent use of these medications. 4
- The combination has been extensively studied and demonstrates excellent tolerability with a safety profile similar to monotherapy with either agent alone. 2
- Both medications can be taken without regard to timing relative to each other, though montelukast is typically recommended in the evening based on its pharmacodynamic profile. 5, 6
Enhanced Efficacy
- Combination therapy with montelukast plus antihistamines (including cetirizine/levocetirizine, the active enantiomer of cetirizine) provides superior symptom control compared to either medication alone. 2, 7, 3
- A randomized controlled trial demonstrated that montelukast combined with levocetirizine significantly reduced daytime nasal symptom scores more than montelukast alone (P = 0.045), with greater improvements across all allergic rhinitis endpoints. 2
- The combination produces greater reductions in eosinophil cationic protein levels (a marker of allergic inflammation) than monotherapy with either agent. 3
Clinical Context
- For persistent allergic rhinitis, combination therapy is considered a more effective strategy than monotherapy. 7
- However, it's important to note that intranasal corticosteroids remain more effective than the combination of antihistamines plus leukotriene antagonists for allergic rhinitis control. 8
- The combination is particularly useful when quality of life is impaired by persistent allergic rhinitis symptoms. 1
Dosing Recommendations
Adults
Pediatric Dosing (if applicable)
- Children 6-14 years: Montelukast 5 mg with cetirizine/levocetirizine 5 mg once daily 5
- Children 2-5 years: Montelukast 4 mg with levocetirizine 1.25 mg twice daily 5
Important Safety Considerations
FDA Black Box Warning
- Monitor for neuropsychiatric events when taking montelukast. The FDA has issued a black box warning regarding potential mood changes, depression, and suicidal thoughts. Patients should be monitored for unusual behavioral or mood changes when starting this medication. 4, 6
Onset of Action
- Montelukast begins producing clinical benefits within 1-2 days of starting therapy, providing continuous control rather than acute symptom relief. 6
- Cetirizine typically provides symptom relief within hours of administration. 9