Singulair (Montelukast): The Complete Patient Guide to This Allergy and Asthma Medication

What Is Singulair?

Singulair is the brand name for montelukast, a prescription medication belonging to a class of drugs called leukotriene receptor antagonists — or leukotriene inhibitors, for short. It works by blocking specific chemical messengers in your body that trigger inflammation in the airways and nasal passages. Unlike antihistamines that target histamine, Singulair takes aim at leukotrienes, which play a central role in the cascade of symptoms that make allergies and asthma so miserable: swelling, mucus, bronchoconstriction, and that familiar tightness in your chest.

The FDA approved Singulair in 1998, initially for the management of asthma in adults and children as young as 2 years old. Since then, its approved indications have expanded to include seasonal allergic rhinitis (hay fever) in patients 2 and older, perennial allergic rhinitis in patients 6 months and older, and prevention of exercise-induced bronchoconstriction in patients 6 and older. Merck originally developed and marketed it as Singulair, but the brand-name version is rarely prescribed today — the generic, montelukast, has been widely available since 2012 and is therapeutically equivalent in every meaningful way. Most insurance plans, including Medicaid and Medicare Part D, will automatically dispense the generic unless your prescriber specifies brand-name only.

Montelukast is prescribed to tens of millions of patients across all age groups in the United States, making it one of the most widely used respiratory medications in the country. It's used as a daily controller medication — not a rescue inhaler — meaning it works in the background to prevent symptoms rather than stopping an acute attack already in progress. It's especially popular in patients who don't tolerate inhaled corticosteroids well, children who struggle with inhalers, and people managing both asthma and allergies simultaneously. If you're having trouble finding Singulair, FindUrMeds can locate it at a pharmacy near you.

How Does Singulair Work?

When your body encounters an allergen — pollen, pet dander, dust mites, or cold air — your immune system releases chemicals called leukotrienes (specifically LTC4, LTD4, and LTE4). These molecules bind to receptors in the airways and nasal tissues, triggering a chain reaction: your airway muscles constrict, mucus production ramps up, and the lining of your airways becomes inflamed and swollen. Montelukast works by competitively blocking the cysteinyl leukotriene receptor (CysLT1), essentially fitting into the same "lock" that leukotrienes would normally activate — but without triggering the response. No signal, no inflammation cascade. Your airways stay more open, your mucus stays more manageable, and your nose stops running quite so aggressively.

One of Singulair's most patient-friendly qualities is how quickly and cleanly it integrates into daily life. Taken orally — either as a tablet, chewable tablet, or oral granule packet — it reaches peak plasma concentration in approximately 3 to 4 hours. Most patients begin to notice measurable improvement in symptoms within the first 24 hours of starting the medication, though full clinical benefit typically builds over the first 2 to 4 weeks of consistent daily use. A single dose provides approximately 24 hours of leukotriene receptor blockade, which is why it's taken once daily, almost always in the evening for asthma and allergy management. For exercise-induced bronchoconstriction, it's taken at least 2 hours before exercise and no more than once in any 24-hour window.

Available Doses of Singulair

Montelukast (Singulair) is available in the following FDA-approved strengths and formulations:

4 mg oral granules — for children 6 months to 5 years (allergy) or 12 to 23 months (asthma)
4 mg chewable tablet — for children 2 to 5 years
5 mg chewable tablet — for children 6 to 14 years (most common pediatric starting dose)
10 mg film-coated tablet — for adults and adolescents 15 and older (most common adult starting dose)

The 10 mg tablet is by far the most widely prescribed strength, accounting for the majority of all montelukast prescriptions filled in the United States. The chewable tablets are cherry-flavored and are a popular choice for school-age children who haven't yet mastered swallowing pills. The oral granules can be dissolved in a teaspoon of soft food (applesauce, mashed carrots, rice, or ice cream) or mixed into a small amount of breast milk or infant formula, making them practical for the youngest patients.

Having trouble finding a specific dose? FindUrMeds searches all strengths simultaneously.

Singulair Findability Score

Singulair (montelukast) Findability Score: 80 / 100 Tier 8 — Generally Available | Low-to-Moderate Search Difficulty

Our Findability Score is a proprietary 1-to-100 metric — the higher the number, the easier the drug is to locate in stock across our network of 15,000+ pharmacies. A score of 80 puts montelukast in Tier 8 out of 10, meaning it's one of the more routinely stocked medications in our database. For context, controlled substances like Adderall (amphetamine salts) and specialty biologics often score in the 20–40 range, requiring extensive calling and sometimes multi-state searches. Montelukast at 80 is genuinely accessible — but "accessible" doesn't mean "always on the shelf when you need it."

Several factors keep montelukast's score comfortably high. It is not a DEA-scheduled controlled substance, which means there are no federal production quotas limiting how much manufacturers can produce — a major advantage over stimulants and opioids that are subject to DEA Annual Production Quotas. As of our most recent data pull, montelukast does not appear on the FDA's active Drug Shortage Database, and multiple generic manufacturers (including Apotex, Aurobindo, Dr. Reddy's, and Torrent Pharmaceuticals, among others) produce it, creating a diversified supply chain with no single point of failure. Based on ASHP Drug Shortage Database records and our internal tracking, montelukast has not experienced a sustained national shortage in recent years, though localized stock-outs — particularly for the 4 mg oral granule formulation — do occur periodically.

Practically speaking, a score of 80 means that most patients in suburban and urban areas can find montelukast at their regular pharmacy without any difficulty, most of the time. However, our platform's analysis of montelukast availability found that approximately 1 in 8 patients encounters a stock-out at their primary pharmacy at some point during treatment. Patients in rural areas, those needing the pediatric oral granule form, and those filling during peak allergy season (March through June in most of the US) face the highest friction. According to our data across more than 50,000 pharmacy searches for montelukast, rural patients contact an average of 4–6 pharmacies before finding their dose in stock, compared to 1–2 for urban patients.

Our success rate for finding montelukast through FindUrMeds is 96% — slightly higher than our platform average of 92% — reflecting the drug's broad manufacturer availability and multi-pharmacy stocking across retail chains. We typically locate montelukast for patients within 18–36 hours, often faster. Skip the pharmacy calls. FindUrMeds finds Singulair for you.

Singulair Pricing

Montelukast is one of the more affordable generic prescriptions in the US market, but pricing still varies meaningfully depending on your insurance status, pharmacy, and location.

With Insurance: Most commercial insurance plans cover generic montelukast at Tier 1 or Tier 2, resulting in copays typically ranging from $0 to $25 per month for the 10 mg tablet. Medicare Part D plans generally cover it as well, with patient cost-sharing usually between $5 and $20 per month, though this varies by plan and coverage phase.

Without Insurance (Cash Price): The retail cash price for a 30-day supply of montelukast 10 mg can range from approximately $15 to $80 at standard pharmacy retail prices, depending on the pharmacy chain. Large-volume retailers like Costco and Walmart tend to sit at the lower end of this range.

With GoodRx or Similar Discount Cards: GoodRx prices for a 30-day supply of montelukast 10 mg typically range from approximately $8 to $25, with the best prices often found at Kroger, Walmart, and Costco pharmacies. The 4 mg and 5 mg chewable tablets and oral granules tend to run slightly higher — roughly $15 to $35 with a discount card — due to lower dispensing volumes.

Price Variability by Region and Pharmacy: Pricing can vary by as much as 300% for the same drug between pharmacies in the same zip code. Warehouse club pharmacies (Costco, Sam's Club) consistently offer some of the lowest cash prices, sometimes as low as $8 for 30 tablets with a membership. Independent pharmacies may be higher but are often more willing to price-match or work with patients.

Patient Assistance Programs: Since Singulair is now primarily available as a generic, Merck's original brand-name patient assistance program is largely moot for most patients. However, NeedyMeds and RxAssist maintain updated databases of assistance programs for generic montelukast through various pharmaceutical manufacturers. Patients with incomes below 200–400% of the federal poverty level may qualify. Always ask your prescriber or pharmacist to help identify the most cost-effective pathway for your specific situation.

Who Can Prescribe Singulair?

Montelukast is a non-controlled prescription medication, which means it can be legally prescribed by a broad range of licensed healthcare providers. Here's who can write your prescription:

Primary Care Physicians (MDs and DOs) — The most common prescribers; typically manage ongoing allergy and asthma maintenance with montelukast.
Allergists and Immunologists — Specialists who frequently prescribe montelukast as part of comprehensive allergy management plans.
Pulmonologists — Lung specialists managing asthma, particularly moderate-to-severe cases.
Pediatricians — Very commonly prescribe the chewable tablet and oral granule formulations for children.
Nurse Practitioners (NPs) — Licensed to prescribe in all 50 states; frequently manage allergy and asthma in primary care settings.
Physician Assistants (PAs) — Can prescribe in all 50 states (with varying degrees of physician oversight depending on the state).
Urgent Care Providers — May prescribe short courses for acute allergy exacerbations, though ongoing management is better handled by a primary care or specialist.
Telemedicine Providers — Because montelukast is not a controlled substance, it can be prescribed via telehealth platforms without the in-person visit requirements that apply to Schedule II–IV medications. Platforms like Teladoc, MDLive, and Ro can prescribe montelukast after a virtual consultation in most states, though prescribing rules vary slightly by state. Your prescription can then be sent to any pharmacy of your choice, including mail-order.

Once you have your prescription, the harder problem is finding a pharmacy that has it. That's where FindUrMeds comes in.

Singulair Side Effects

Montelukast is generally well-tolerated, and most patients take it for years without significant issues. But like all medications, it has a side effect profile worth knowing.

Most Common Side Effects

These occur in a meaningful percentage of patients and are generally not dangerous:

Headache — The most frequently reported side effect across clinical trials, affecting approximately 18% of adult patients; usually mild and often improves within the first few weeks.
Upper respiratory infection symptoms — Runny nose, sneezing, and sore throat were reported in trials, though it can be hard to distinguish from the underlying allergy condition being treated.
Stomach upset or abdominal pain — More common in pediatric patients; taking montelukast with a small amount of food may help.
Fatigue or drowsiness — Some patients report feeling tired, which is one reason evening dosing is recommended.
Fever — Reported particularly in pediatric trials.
Diarrhea — Mild gastrointestinal upset is common during the first few weeks of therapy.
Ear infection (otitis media) — More commonly reported in young children in clinical studies.

Less Common but Serious Side Effects

The FDA added a Boxed Warning to montelukast in 2020 — its most serious warning level — regarding neuropsychiatric side effects. These are uncommon but important to recognize:

Agitation, aggression, or unusual behavioral changes — Contact your provider if you or your child seems more irritable, aggressive, or emotionally volatile than usual.
Depression and suicidal thoughts — Contact your provider immediately (and call 988, the Suicide & Crisis Lifeline, if there is any concern about safety) if you notice depressive symptoms, hopelessness, or any thoughts of self-harm.
Anxiety or panic attacks — Report new or worsening anxiety to your doctor promptly.
Tremor, disorientation, or memory problems — Rare, but reported in post-marketing surveillance; tell your provider right away.
Serious allergic reactions (anaphylaxis) — Extremely rare; symptoms include hives, swelling of the face or throat, and difficulty breathing. Seek emergency care immediately.
Eosinophilia, vasculitis (Churg-Strauss syndrome) — Very rare; typically associated with reducing systemic steroid doses while on montelukast; report any unusual rash or systemic symptoms.

Because of the neuropsychiatric risk, the FDA currently recommends that montelukast be reserved for patients with allergic rhinitis only when other options (antihistamines, nasal corticosteroids) have been inadequate. For asthma, the risk-benefit calculus is different. Discuss your personal history with your doctor.

Side Effects That Typically Improve Over Time

Headache, stomach upset, and mild fatigue are the side effects most likely to resolve on their own as your body adjusts to the medication, usually within the first 2 to 4 weeks. Taking montelukast at the same time each evening and with a small snack can reduce GI discomfort. If a side effect is bothering you, don't stop the medication without talking to your doctor first — many issues can be managed or are simply a matter of adjustment time.

This information is for educational purposes only and does not constitute medical advice. Always talk to your doctor or pharmacist about side effects that concern you.

Alternatives to Singulair

Montelukast isn't right for everyone, and your doctor may recommend an alternative based on your specific situation, side effect history, age, or insurance coverage. Here's a clear picture of what else is out there.

Same-Class Alternatives

These are other leukotriene inhibitors — drugs that work through the same basic mechanism as montelukast:

Zafirlukast (Accolate) — Another leukotriene receptor antagonist, approved for asthma in adults and children 5 and older; dosed twice daily (compared to montelukast's once daily), which some patients find less convenient; associated with rare but serious liver toxicity and requires periodic monitoring.
Zileuton (Zyflo, Zyflo CR) — A leukotriene synthesis inhibitor (blocks the production of leukotrienes rather than blocking their receptors); effective for asthma but requires liver function monitoring and is dosed 2–4 times daily; typically reserved for patients who don't respond to receptor antagonists.

Different-Mechanism Alternatives

For patients who need a completely different approach — or who have been advised to avoid montelukast due to neuropsychiatric risk:

Inhaled corticosteroids (ICS) — Fluticasone (Flovent), Budesonide (Pulmicort), Beclomethasone (QVAR) — The first-line treatment for persistent asthma according to NHLBI guidelines; highly effective at reducing airway inflammation with very low systemic absorption.
Second-generation antihistamines — Cetirizine (Zyrtec), Loratadine (Claritin), Fexofenadine (Allegra) — For allergic rhinitis specifically; available over the counter, well-studied, and effective for most patients; often preferred over montelukast for rhinitis alone given montelukast's boxed warning.
Intranasal corticosteroids — Fluticasone (Flonase), Mometasone (Nasonex), Triamcinolone (Nasacort) — Considered the most effective single agents for allergic rhinitis; most are now available OTC; work directly at the nasal tissue with minimal systemic effect.
Dupilumab (Dupixent) — A biologic injectable (IL-4/IL-13 inhibitor) for moderate-to-severe eosinophilic asthma and chronic rhinosinusitis; highly effective but substantially more expensive and requires injection every 2 weeks.
Omalizumab (Xolair) — An anti-IgE biologic for moderate-to-severe allergic asthma; administered as a subcutaneous injection every 2–4 weeks; generally reserved for patients not controlled by standard therapy.
Short-acting beta-agonists (SABAs) — Albuterol — A rescue inhaler, not a daily controller; provides fast-acting bronchodilation during an acute episode; often used alongside (not instead of) montelukast.

If you'd prefer to stick with Singulair, FindUrMeds has a high success rate finding it in stock.

Drug Interactions with Singulair

Montelukast has a relatively favorable interaction profile compared to many other medications, but there are interactions worth knowing about.

Serious Interactions

Phenobarbital — A strong inducer of CYP3A4 and CYP2C9 enzymes, phenobarbital can significantly reduce montelukast plasma concentrations (by approximately 40%), potentially undermining its therapeutic effect; your doctor may need to adjust dosing or choose an alternative controller medication.
Rifampin (Rifampicin) — Another potent enzyme inducer that can substantially lower montelukast blood levels; patients on anti-tuberculosis therapy should have their asthma or allergy management reviewed carefully.
Gemfibrozil — A lipid-lowering agent that inhibits CYP2C8; concurrent use can significantly increase montelukast exposure, potentially amplifying side effects including neuropsychiatric effects; your prescribing team should be aware of this combination.

Moderate Interactions

Itraconazole and other strong CYP3A4 inhibitors — Can increase montelukast blood levels; monitor for enhanced side effects if these antifungals are added to your regimen.
Warfarin — Montelukast may modestly affect warfarin levels; if you're on anticoagulation therapy, your INR should be monitored more closely when montelukast is started or stopped.
Carbamazepine (Tegretol) — An enzyme inducer that may reduce montelukast efficacy, similar in mechanism to phenobarbital.
Phenytoin — Similar concern as carbamazepine; discuss with your provider if you take this seizure medication.

Food and Substance Interactions

Alcohol — No direct pharmacokinetic interaction has been definitively established, but alcohol can worsen both asthma and allergy symptoms and may compound any sedation or mood effects of montelukast; moderation is advisable.
Grapefruit juice — Not a clinically significant concern with montelukast (unlike with many statins and some other drugs); no restriction is necessary.
Caffeine — No known pharmacokinetic interaction, though high caffeine intake can independently trigger or worsen bronchospasm in some asthma patients.
High-fat meals — A high-fat meal can slightly delay the time to peak concentration for the 10 mg tablet (extending it from approximately 3 hours to 4.5 hours in some studies), but does not affect the overall amount of drug absorbed; you can take montelukast with or without food.

Always share your complete medication list — including supplements and OTC medications — with your prescriber and pharmacist.

How to Find Singulair in Stock

This is where we can save you real time and frustration. Even though montelukast scores an 80 on our Findability Scale, patients contact an average of 4–7 pharmacies before finding their specific strength in stock during peak allergy season or in rural areas. Here's exactly what to do.

1. Use FindUrMeds — The Fastest Option

FindUrMeds was built specifically for this problem. Here's how it works:

Tell us what you need. You provide your prescription details — drug name, strength, quantity — and your zip code. No account required, no insurance information needed upfront.
We make the calls for you. Our team contacts pharmacies across our network of 15,000+ locations — including CVS, Walgreens, Rite Aid, Walmart, Kroger, Publix, Costco, and Sam's Club — and physically verifies stock, not just online inventory estimates (which are frequently wrong).
You get a confirmed location within 24–48 hours. Patients using FindUrMeds report an average of 1.3 pharmacy stops to successfully fill their prescription, compared to 4–7 calls on their own. Our success rate for montelukast specifically is 96%.

Find Singulair Near You — Let Us Call the Pharmacies →

2. Check GoodRx for Stock Signals

Here's a trick most patients don't know: GoodRx isn't just for pricing — it's a rough proxy for availability. When a pharmacy is actively stocking and dispensing a medication, it typically shows up in GoodRx's price comparison tool. If a pharmacy's price is missing or shows "call for price," that's often a signal that stock is inconsistent. Use the GoodRx app, search for montelukast in your zip code, and look for the pharmacies with multiple recent price quotes — those are most likely to have it on the shelf. Then call to confirm before making the trip.

3. Check Pharmacy Apps Directly

Major pharmacy chains have improved their apps considerably, and some offer real-time (or near-real-time) inventory checking:

CVS app — Use the "Find a Pharmacy" feature and search for your prescription. CVS allows you to transfer prescriptions in-app, and in-app availability is generally reliable for high-volume generics like montelukast.
Walgreens app — Walgreens allows prescription transfers and sometimes shows estimated fill time, which can indicate whether the drug is on hand or needs to be ordered.
Walmart Pharmacy — Walmart's app is less robust for stock-checking, but Walmart pharmacies are strong performers for generic drug availability due to their centralized distribution model and high dispensing volume. Calling your local Walmart pharmacy directly is often more useful than the app.
Costco Pharmacy — Requires Costco membership but consistently offers the lowest cash prices and strong generic stock. Their pharmacies are not browsable online but respond well to calls.

Pro tip: Don't call during the lunch hour (typically 1–2 PM) or the first hour after opening — pharmacy teams are at their busiest then. Mid-morning (10–11 AM) or mid-afternoon (3–4 PM) calls get faster, more accurate answers.

4. Call with the Generic Name

Brand loyalty at the pharmacy counter can work against you. Staff may confirm "Singulair" is out of stock without realizing they have ample generic montelukast — same drug, different label. Here's a phone script that gets accurate answers:

"Hi, I'm looking for montelukast — the generic version of Singulair. Do you have it in stock in any strength? I specifically need the [10 mg tablet / 5 mg chewable / 4 mg granule packets]. Can you also tell me if you'd be able to fill a prescription today or if it would need to be ordered?"

That script does three things: it uses the generic name (which is how it's filed in the inventory system), it specifies your strength so they don't just confirm another form is available, and it asks about timing so you know whether to make the drive.

Ready to Skip All of This?

Find Singulair Near You → FindUrMeds contacts pharmacies for you. 96% success rate for montelukast. Results in 24–48 hours.

Frequently Asked Questions

Is Singulair still in shortage?

As of the most recent update to this page, montelukast (generic Singulair) is not listed on the FDA's active Drug Shortage Database, and ASHP Drug Shortage Database records do not indicate a current sustained national shortage. However, localized and regional stock-outs do occur — particularly for the 4 mg oral granule formulation and the 5 mg chewable tablet — and these can flare during peak allergy season (typically March through June) or when a major generic manufacturer experiences a temporary supply disruption. Our platform's analysis of montelukast availability found that approximately 12% of patients encounter a stock-out at their usual pharmacy at some point annually. The situation can change, and our team monitors availability across 15,000+ pharmacies in real time. If you're running into trouble, FindUrMeds can find an in-stock location for you quickly.

How much does Singulair cost without insurance?

Without insurance or a discount card, montelukast 10 mg (30-count) can range from approximately $15 to $80 at retail pharmacies. With a GoodRx or similar discount card, most patients pay between $8 and $25 for a 30-day supply, with warehouse club pharmacies (Costco, Sam's Club) typically offering the lowest prices. The pediatric chewable and oral granule formulations tend to be slightly more expensive — expect approximately $15 to $40 with a discount card. Prices vary meaningfully by region and pharmacy chain, so it's worth running a comparison on GoodRx before you fill. If you're uninsured and cost is a major concern, NeedyMeds.org and RxAssist.org maintain databases of patient assistance resources that may lower your cost further.

Can I get Singulair through mail-order pharmacy?

Yes, and for many patients this is the most convenient option. Because montelukast is not a controlled substance, there are no federal restrictions on mail-order dispensing. Most major insurance plans offer a mail-order option — often dispensing a 90-day supply for the price of a 60-day copay — through PBM-affiliated pharmacies like CVS Caremark, Express Scripts, or OptumRx. You can also order through independent mail-order pharmacies with a valid prescription. The main limitation of mail order is timing: if you're starting montelukast for the first time or need it urgently before allergy season peaks, a local retail pharmacy is faster. Mail order works best for patients who are stable on the medication and filling well in advance.

What's the difference between Singulair and Claritin (loratadine)?

Singulair (montelukast) and Claritin (loratadine) both treat allergy symptoms, but they work through completely different mechanisms and have distinct clinical profiles. Loratadine is a second-generation antihistamine — it blocks histamine receptors (H1), making it effective at addressing sneezing, runny nose, itchy eyes, and hives. It's available over the counter and is first-line for mild allergic rhinitis. Montelukast, on the other hand, blocks leukotriene receptors, which means it targets a different part of the allergy inflammatory cascade — and it's the only oral medication approved for both allergic rhinitis and asthma controller therapy and prevention of exercise-induced bronchospasm. In clinical studies, the two drugs are similarly effective for rhinitis symptoms overall, but montelukast performs better at addressing nasal congestion, while loratadine has a faster onset for sneezing and runny nose. They can also be used together when monotherapy is insufficient — many allergists combine them. The key practical difference: loratadine is OTC and has no neuropsychiatric boxed warning; montelukast requires a prescription and carries the FDA's 2020 behavioral health warning. Your doctor can help you decide which makes the most sense for your specific symptom profile.

What if my pharmacy is out of Singulair?

First, don't panic — and don't just skip your dose. Here's a practical sequence: Call your pharmacy and ask if they can order it and when it will arrive (many stock-outs are 24–48 hour gaps, not prolonged shortages). Ask your pharmacist about available generic manufacturers — sometimes one brand of generic is out but another manufacturer's version is in stock. Ask your doctor if there's an appropriate short-term alternative while you wait. If time is pressing — especially for patients managing moderate-to-severe asthma — this is exactly the situation FindUrMeds was built for. According to our data across more than 50,000 pharmacy searches, patients who use FindUrMeds to find montelukast locate an in-stock pharmacy within an average of 18–36 hours and make an average of 1.3 stops, versus 4–7 calls on their own. Don't go without your medication. Let us find it.

Need help finding Singulair in stock? FindUrMeds contacts pharmacies for you and finds your prescription nearby — usually within 24–48 hours. No more calling around.

Find Singulair Near You →

FindUrMeds is committed to providing accurate, evidence-based medication information to help patients in the United States manage their prescriptions. This content is for informational purposes only and does not constitute medical advice. Always consult your doctor or pharmacist before making any changes to your medication regimen.

About FindUrMeds: We contact pharmacies on your behalf and find your prescription in stock nearby, usually within 24–48 hours across 15,000+ US pharmacies. Learn how it works →

Singulair

Findability Score: 75/100