Singulair vs Allegra: side-by-side comparison
Singulair (Respiratory Medications) and Allegra (Allergy and Antihistamines) belong to different therapeutic classes and are rarely interchangeable. This page compares the medications' purposes, mechanisms and the situations where each is used.
| Property | Singulair | Allegra |
|---|---|---|
| Active ingredient | Montelukast | Fexofenadine |
| Manufacturer | Organon | Sanofi |
| Class | Respiratory Medications | Allergy and Antihistamines |
| Strengths | 4mg, 5mg, 10mg | 30mg, 60mg, 120mg, 180mg |
| Forms | tablet, chewable tablet, oral granules | tablet, oral suspension, orodispersible tablet |
What's the same
Singulair and Allegra 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
Singulair belongs to Respiratory Medications while Allegra belongs to Allergy and Antihistamines. 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
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. Allegra: Fexofenadine selectively blocks peripheral H1 histamine receptors, antagonising the effects of histamine on vasodilation, capillary permeability, sensory nerve endings and smooth muscle.
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.
When Allegra is preferred
Allegra is approved in adults and children for the treatment of seasonal allergic rhinitis and chronic idiopathic urticaria.
Frequently asked questions
Is Singulair or Allegra better? ▾
Singulair and Allegra 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 Singulair to Allegra? ▾
Switching between Singulair and Allegra 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 Singulair and Allegra 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 Singulair comparisons
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.