Allegra vs Singulair: side-by-side comparison
Allegra (Allergy and Antihistamines) and Singulair (Respiratory Medications) belong to different therapeutic classes and are rarely interchangeable. This page compares the medications' purposes, mechanisms and the situations where each is used.
| Property | Allegra | Singulair |
|---|---|---|
| Active ingredient | Fexofenadine | Montelukast |
| Manufacturer | Sanofi | Organon |
| Class | Allergy and Antihistamines | Respiratory Medications |
| Strengths | 30mg, 60mg, 120mg, 180mg | 4mg, 5mg, 10mg |
| Forms | tablet, oral suspension, orodispersible tablet | tablet, chewable tablet, oral granules |
What's the same
Allegra and Singulair are used in very different patients, and the points in common are limited. The main shared element is that both meet regulatory standards for efficacy and safety and benefit from pharmacist oversight.
Key differences
Allegra belongs to Allergy and Antihistamines while Singulair belongs to Respiratory Medications. Indications, mechanisms and target populations differ. The comparison is most useful when a clinician has mentioned both medications and the patient wants to understand where each fits.
Mechanism and action
Allegra: Fexofenadine selectively blocks peripheral H1 histamine receptors, antagonising the effects of histamine on vasodilation, capillary permeability, sensory nerve endings and smooth muscle. Singulair: Montelukast selectively blocks the CysLT1 receptor, which mediates the action of leukotrienes C4, D4 and E4 — proinflammatory mediators released by mast cells and eosinophils.
When Allegra is preferred
Allegra is approved in adults and children for the treatment of seasonal allergic rhinitis and chronic idiopathic urticaria.
When Singulair is preferred
Singulair is approved in adults and children for the maintenance treatment of asthma, including exercise-induced bronchospasm, and for the treatment of seasonal and perennial allergic rhinitis when conventional therapy is insufficient or not tolerated.
Frequently asked questions
Is Allegra or Singulair better? ▾
Allegra and Singulair are not interchangeable — they treat different conditions. Asking which is "better" is meaningful only when a clinician has weighed both for the same specific clinical scenario.
Can I switch from Allegra to Singulair? ▾
Switching between Allegra and Singulair is rarely an appropriate decision since they belong to different classes and treat different conditions. The real question is usually whether the diagnosis calls for one medication or the other — which the prescriber resolves.
Do Allegra and Singulair have the same side effects? ▾
No — they belong to different classes and have distinct side-effect profiles. Each medication has its own prescribing information.
More Allegra comparisons
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.