Singulair is not a steroid. It belongs to a completely different class of medications called leukotriene receptor antagonists (LTRAs). While Singulair and steroids both reduce inflammation in the airways, they do so through entirely separate biological pathways, carry different side effect profiles, and play different roles in treatment plans.
How Singulair Actually Works
Your body produces chemicals called leukotrienes during an allergic or asthmatic response. These chemicals trigger airway narrowing, mucus production, swelling, and the migration of inflammatory cells into your airways. Singulair (generic name: montelukast) blocks the receptor that leukotrienes latch onto, preventing them from causing those reactions in the first place.
This is fundamentally different from how steroids work. Inhaled corticosteroids, the most common controller medications for asthma, broadly suppress inflammation across multiple pathways in the airways. They’re effective, but they cast a wide net. Singulair targets one specific piece of the inflammatory chain. Notably, the inflammatory signals that Singulair blocks are not suppressed by corticosteroids at all, which is why the two medications are sometimes prescribed together.
Why People Confuse Singulair With Steroids
The confusion makes sense. Singulair is prescribed for the same conditions that steroid inhalers treat: asthma, seasonal allergies, and exercise-triggered breathing problems. It’s a daily pill used for long-term control, just like a steroid inhaler. And doctors sometimes prescribe it alongside or instead of inhaled steroids, which blurs the line further.
But the distinction matters. Long-term oral steroid use can cause weight gain, bone density loss, blood sugar changes, and immune suppression. Inhaled steroids carry lower risks but can still cause oral thrush and hoarseness. Singulair doesn’t carry any of those steroid-related side effects because it doesn’t interact with the same hormonal pathways.
What Singulair Is Prescribed For
The FDA has approved Singulair for three uses:
- Asthma prevention and long-term control in patients 12 months and older
- Exercise-induced breathing difficulty in patients 6 years and older
- Allergic rhinitis (hay fever), including seasonal allergies in patients 2 years and older and year-round allergies in patients as young as 6 months
It comes as a daily tablet: a 4 mg chewable for young children, a 5 mg chewable for older children, and a 10 mg tablet for adults. It’s taken once a day, typically in the evening for asthma or at any consistent time for allergies. One important limitation: Singulair does not stop an asthma attack that’s already happening. It’s a preventive medication, not a rescue inhaler.
How It Compares to Inhaled Steroids for Asthma
For most people with persistent asthma, inhaled corticosteroids are considered the stronger first-line treatment. They directly reach the airways and broadly reduce the inflammation that drives asthma symptoms. Singulair is generally considered a step below in potency for asthma control, but it has real advantages in certain situations: it’s a pill instead of an inhaler (easier for young children or people who struggle with inhaler technique), it has no steroid-related side effects, and it can be added on top of an inhaled steroid when one medication alone isn’t enough.
For allergic rhinitis specifically, the FDA now recommends that Singulair not be used as a first-choice treatment, given that effective alternatives like antihistamines and nasal steroid sprays are available with fewer concerns.
Side Effects to Know About
Singulair’s common side effects are mild: upper respiratory infections, headache, sore throat, cough, stomach pain, and fever. These are quite different from the metabolic and hormonal side effects associated with systemic steroids.
However, Singulair carries a serious warning that steroids do not. In 2020, the FDA added its strongest warning label, a Boxed Warning, to Singulair’s prescribing information based on reports of significant mental health side effects. These include mood changes, agitation, depression, anxiety, vivid or disturbing dreams, trouble sleeping, confusion, hallucinations, and in rare cases, suicidal thoughts. Some of these effects resolved after stopping the medication, while others persisted even after discontinuation.
This doesn’t mean everyone who takes Singulair will experience these effects. But it’s worth being aware of mood or behavioral changes, particularly in children, who may not recognize or articulate what they’re feeling. If you notice personality shifts, sleep disruptions, or new anxiety after starting the medication, that’s worth a conversation with your prescriber about whether to continue.
The Bottom Line on Drug Class
Singulair and steroids sit in completely separate pharmacological categories. Steroids mimic hormones your body naturally produces and dial down inflammation broadly. Singulair blocks one specific inflammatory molecule, leukotriene, at its receptor. They treat overlapping conditions, which is why they’re easy to conflate, but they work differently, feel different in your body, and carry different risks. If you’ve been prescribed Singulair specifically because you or your doctor wanted to avoid steroids, that goal is being met.