Singulair vs Plan B: side-by-side comparison
Singulair (Respiratory Medications) and Plan B (Hormones and Birth Control) 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 | Plan B |
|---|---|---|
| Active ingredient | Montelukast | Levonorgestrel |
| Manufacturer | Organon | Foundation Consumer Healthcare |
| Class | Respiratory Medications | Hormones and Birth Control |
| Strengths | 4mg, 5mg, 10mg | 1.5mg |
| Forms | tablet, chewable tablet, oral granules | tablet |
What's the same
Singulair and Plan B 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 Plan B belongs to Hormones and Birth Control. 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. Plan B: Plan B's primary mechanism is delaying or preventing ovulation when taken before the LH surge.
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 Plan B is preferred
Plan B is indicated for emergency contraception after unprotected intercourse or known/suspected contraceptive failure, in women of reproductive age.
Frequently asked questions
Is Singulair or Plan B better? ▾
Singulair and Plan B 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 Plan B? ▾
Switching between Singulair and Plan B 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 Plan B 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.