Montelukast Sodium
Pronunciation: (mon-teh-LOO-kast).
- Generic name
- Montelukast sodium
- Brand names
- Singulair
- Drug class
- Leukotriene receptor antagonist (LTRA)
Availability and supply rules vary by country
Trade names by country: United States · Canada
Australia: · Full directory
What Montelukast sodium is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how Montelukast sodium works
Montelukast is an oral leukotriene receptor antagonist that blocks leukotrienes, chemical mediators involved in airway inflammation, and thereby reduces airway inflammation in asthma and allergic disease. (2)
What Montelukast sodium is used for
Prophylaxis and chronic treatment of asthma in patients 12 months of age and older
Not indicated for treating acute asthma attacks. (1)
Prevention of exercise-induced bronchoconstriction in patients 6 years of age and older
Prevention of exercise-induced bronchoconstriction in patients 6 years of age and older (1)
Allergic rhinitis — seasonal (ages 2 years and older) and perennial (ages 6 months and older)
Because of the neuropsychiatric-events risk, use for allergic rhinitis is generally reserved for patients who have had an inadequate response to, or cannot tolerate, alternative therapies. (1)
Before taking Montelukast sodium
Do not take / not appropriate for
- hypersensitivity to any component of the product. (Contraindication) (1)
Tell your clinician about
(1)How to take Montelukast sodium
- Take montelukast exactly as prescribed, once daily — in the evening for asthma or allergic rhinitis, or about 2 hours before exercise for exercise-induced bronchoconstriction. Oral granules must be used within 15 minutes of opening the packet — they can be placed directly in the mouth or mixed with a spoonful of cold or room-temperature baby formula, breast milk, or one of these specific soft foods only: applesauce, carrots, rice, or ice cream. Do not mix granules with any liquid other than formula or breast milk, and do not store a pre-mixed dose for later use. The FDA label states film-coated tablets and chewable tablets are taken orally, with or without food, and does not give any further special handling technique beyond chewing the chewable tablet as normal; patients who miss a dose should take the next dose at their regular time and should not take two doses at the same time. Montelukast is not a rescue medication for sudden asthma symptoms.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)
Missed dose
If you miss a dose, take your next dose at the regular time — do not take an extra dose to make up for the one you missed.
Overdose
If an overdose is suspected, seek emergency medical attention promptly. There is no specific antidote; a clinician may remove unabsorbed medicine from the stomach and will provide supportive care. It is not known whether dialysis removes montelukast from the body. (1)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Upper respiratory infection, fever, headache, or sore throat (pharyngitis)
Incidence: Common (each reported in 5% or more of patients and more often than with placebo)
Cough, stomach (abdominal) pain, or diarrhea
Incidence: Common (each reported in 5% or more of patients and more often than with placebo)
Ear infection (otitis media), flu, runny nose, or sinusitis
Incidence: Common (each reported in 5% or more of patients and more often than with placebo)
New or worsening mood or behavior changes, agitation, aggression, depression, sleep disturbances, hallucinations, or thoughts of self-harm
What to do: Seek medical attention promptly — this needs urgent clinician assessment. (1)
Signs that may suggest Churg-Strauss syndrome — new rash, worsening breathing problems, numbness/tingling, or chest/heart symptoms
What to do: Seek medical attention promptly. (1)
Any new or concerning symptom that could suggest a liver problem
What to do: Tell your clinician promptly so they can assess whether liver testing is needed. (1)
Any sign of a severe reaction after taking montelukast
What to do: Seek immediate emergency care. (1)
Serious warnings
Boxed warning — serious mental health (neuropsychiatric) effects — serious
Symptoms: Boxed warning — serious mental health (neuropsychiatric) effects: montelukast has been linked to agitation, aggression, depression, sleep disturbances, hallucinations, and suicidal thoughts or behavior. Seek medical attention promptly for any new or worsening mood or behavior changes, or thoughts of self-harm, in yourself or your child — contact your clinician right away for an urgent assessment, and they will advise whether montelukast should be continued or discontinued.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Churg-Strauss syndrome (a rare condition involving inflamed blood vessels) — serious
Symptoms: Churg-Strauss syndrome (a rare condition involving inflamed blood vessels): seek medical attention promptly for a new rash, worsening breathing problems, numbness or tingling, or chest/heart symptoms, especially if you are also reducing a steroid medicine.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Liver problems — serious
Symptoms: Liver problems: cases of liver injury (cholestatic hepatitis, hepatocellular injury, and mixed-pattern liver injury) have been reported, often with other contributing factors present. Tell your clinician promptly about any new symptom that concerns you, and let them assess whether liver testing or a treatment change is needed.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Do not use montelukast in place of your inhaled or oral corticosteroid, and do not reduce or stop a corticosteroid because you have started montelukast — any change to a corticosteroid must be directed by your prescriber — serious
Symptoms: Do not use montelukast in place of your inhaled or oral corticosteroid, and do not reduce or stop a corticosteroid because you have started montelukast — any change to a corticosteroid must be directed by your prescriber.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Tell your prescriber before starting montelukast if you have a known or suspected allergy to montelukast or any ingredient in the product — they will determine whether it is appropriate for you — serious
Symptoms: Tell your prescriber before starting montelukast if you have a known or suspected allergy to montelukast or any ingredient in the product — they will determine whether it is appropriate for you. Seek immediate medical attention for any signs of a severe reaction after taking it.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Phenobarbital | Decreases montelukast levels in the body (AUC reduced by about 40%). No dosage adjustment of montelukast is generally recommended, but your prescriber may monitor more closely. | (1) |
| Rifampin and other potent CYP enzyme inducers | May reduce montelukast levels. Clinical monitoring is recommended if used together. | (1) |
| Theophylline, prednisone, prednisolone, oral contraceptives, fexofenadine, digoxin, warfarin, gemfibrozil, itraconazole, or benzodiazepines | No dose adjustment is needed for montelukast when used with these medicines, based on the source reviewed. | (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Available cohort studies have not established a drug-associated risk of major birth defects; animal studies at doses much higher than the human dose showed no adverse developmental effects. Discuss any pregnancy or plans for pregnancy with your prescriber. (1)
Breastfeeding
Montelukast is present in breast milk; no significant risk to a breastfed infant is anticipated based on available data. Discuss breastfeeding with your prescriber. (1)
Children
Approved for asthma from 12 months of age, exercise-induced bronchoconstriction prevention from 6 years of age, seasonal allergic rhinitis from 2 years of age, and perennial allergic rhinitis from 6 months of age, with age-specific dosing (see professional information). The boxed neuropsychiatric warning applies to children as well as adults — caregivers should watch for mood or behavior changes. (1)
Renal_impairment
Renal: no dosage adjustment is recommended in patients with renal insufficiency; montelukast and its metabolites are not excreted in the urine, so pharmacokinetics were not specifically evaluated in renal impairment, but no adjustment is required. Hepatic: no dosage adjustment is required in patients with mild-to-moderate hepatic insufficiency (a study in patients with mild-to-moderate hepatic insufficiency and clinical evidence of cirrhosis showed a 41% higher mean montelukast AUC and a slightly prolonged half-life, but this did not change the dosing recommendation); pharmacokinetics in more severe hepatic impairment or with hepatitis have not been evaluated. Cases of liver injury have also been reported post-marketing (see serious warnings above). (1)
Hepatic_impairment
Renal: no dosage adjustment is recommended in patients with renal insufficiency; montelukast and its metabolites are not excreted in the urine, so pharmacokinetics were not specifically evaluated in renal impairment, but no adjustment is required. Hepatic: no dosage adjustment is required in patients with mild-to-moderate hepatic insufficiency (a study in patients with mild-to-moderate hepatic insufficiency and clinical evidence of cirrhosis showed a 41% higher mean montelukast AUC and a slightly prolonged half-life, but this did not change the dosing recommendation); pharmacokinetics in more severe hepatic impairment or with hepatitis have not been evaluated. Cases of liver injury have also been reported post-marketing (see serious warnings above). (1)
Monitoring
(1)Storage
Store at 20-25°C (68-77°F); brief excursions between 15-30°C (59-86°F) are permitted. Protect from moisture and light, and keep in the original package.
Study the drug class: Leukotriene receptor antagonists
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General (US label)
Indication: Asthma, exercise-induced bronchoconstriction, and allergic rhinitis
Dose summary: Ages 15+: 10 mg tablet once daily (evening for asthma/allergic rhinitis; 2 hours before exercise for EIB). Ages 6-14: 5 mg chewable tablet once daily (same timing pattern). Ages 2-5: 4 mg chewable tablet or oral granules once daily (asthma or allergic rhinitis; EIB not indicated in this age group). Ages 6-23 months: 4 mg oral granules once daily for asthma, and for perennial allergic rhinitis.
Renal context: The FDA label states no dosage adjustment is recommended in patients with renal insufficiency. Montelukast and its metabolites are not excreted in the urine, so specific pharmacokinetic studies were not conducted in renal impairment, but no dose adjustment is required. (1)
Frequently asked questions
What is montelukast used for?
Montelukast is used to prevent and treat asthma, prevent exercise-induced bronchoconstriction, and treat allergic rhinitis. For allergic rhinitis, it is generally reserved for people who have not responded well to, or cannot tolerate, other allergy treatments, because of the risk of serious mental-health side effects.
Does montelukast have a boxed warning?
Yes. Montelukast carries a boxed warning for serious neuropsychiatric (mental health) events, including agitation, aggression, depression, sleep disturbances, hallucinations, and suicidal thoughts or behavior.
Can I use montelukast during an asthma attack?
No. Montelukast is not indicated for treating acute (sudden) asthma attacks — follow your clinician-provided asthma action plan and seek urgent medical care for a sudden or severe attack.
Is montelukast safe for children?
Montelukast is approved for asthma from 12 months of age, for exercise-induced bronchoconstriction from 6 years, for seasonal allergic rhinitis from 2 years, and for perennial allergic rhinitis from 6 months, with age-specific dosing. The boxed neuropsychiatric warning applies to children as well as adults, so caregivers should watch for mood or behavior changes.
What should I do if I experience mood changes while taking montelukast?
Contact your healthcare provider promptly if you or your child notice mood changes, depression, agitation, hallucinations, or thoughts of self-harm. These need urgent clinician assessment.
Can I take montelukast with other allergy or asthma medications?
Montelukast is generally used alongside other asthma or allergy medications, and you should not reduce or stop an inhaled or oral corticosteroid because you have started montelukast unless your prescriber directs it. Always tell your doctor or pharmacist about all medicines and supplements you take.
What are the most common side effects of montelukast?
Common side effects (each reported in 5% or more of patients in trials) include upper respiratory infection, fever, headache, sore throat, cough, stomach pain, diarrhea, ear infection, flu, runny nose, and sinusitis.
What is the mechanism of action of Montelukast sodium?
Montelukast is an oral leukotriene receptor antagonist that blocks leukotrienes, chemical mediators involved in airway inflammation, and thereby reduces airway inflammation in asthma and allergic disease. (2)
What is the generic name of Montelukast Sodium?
The generic name is Montelukast sodium. It is sold under brand names including Singulair.
What class of drug is Montelukast sodium?
Montelukast Sodium is classed as: Leukotriene receptor antagonist (LTRA).
References
- SINGULAIR (montelukast sodium) granule, chewable tablet, film-coated tablet — prescribing informationU.S. Food and Drug Administration (DailyMed) · United States · accessed 2026-08-06 · source 1
- Montelukast clinician-authored medicine recordMedGuideGlobal · United States · accessed 2026-08-06 · source 2
- MONTELUKAST TABLET [COUPLER LLC] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 3
- Montelukast — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 4
- montelukast sodium — FDA approval record (Drugs@FDA ANDA204093)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 5
- Montelukast — RxNorm normalized drug concept (RXCUI 88249)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 6
Brand names by country
Single-ingredient Montelukast sodium names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- SINGULAIR10 mg, 5 mg, 4 mg · organon llc
Canada
- SINGULAIR
- ACH-MONTELUKAST
- PMS-MONTELUKAST FC
- DOM-MONTELUKAST FC
- RIVA-MONTELUKAST FC