Montelukast: uses, dosing, side effects & brands

Montelukast sodium, the active ingredient in SINGULAIR, is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene CysLT 1 receptor.

The FDA classifies montelukast as a leukotriene receptor antagonist. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

The elimination half-life of montelukast is about 2.7 to 5.5 hours — that is how long the body takes to clear half of a dose. This is the mean range in healthy young adults; the half-life is somewhat longer in older adults and in people with mild-to-moderate liver impairment (about 7.4 hours). No active metabolite with a materially longer half-life is present. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run montelukast against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

We track 2 montelukast-containing products in the U.S.: Montelukast Sodium and Singulair. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

Across the brands we track, montelukast is currently marketed as powder, tablet and tablet, chewable, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Yes. Our catalog lists 1 generic montelukast product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.

For allergic rhinitis (hay fever), montelukast can ease symptoms within a day. For asthma it's a daily controller, not a rescue medicine — steadier breathing and fewer symptoms build over days to weeks of nightly dosing. It won't stop an asthma attack in progress; keep your rescue inhaler for that. Take it consistently each evening for the full benefit.

The most common side effects of Singulair (montelukast), a leukotriene inhibitor used to prevent asthma symptoms and treat seasonal and perennial allergic rhinitis, are usually mild: headache, stomach (abdominal) pain, heartburn, tiredness, diarrhea, and upper-respiratory symptoms such as cough or a stuffy nose. Per MedlinePlus, these often do not need medical attention unless they persist or bother you. This is not a complete list; check the label or ask your pharmacist about your specific dose and form.

Yes. In 2020 the FDA added its most prominent warning, a Boxed Warning, for serious mental health (neuropsychiatric) side effects. The FDA-listed neuropsychiatric effects include agitation, aggressive behavior or hostility, anxiousness, depression, disorientation, disturbance in attention, dream abnormalities (including nightmares), hallucinations, insomnia, irritability, memory impairment, obsessive-compulsive symptoms, restlessness, stuttering, sleepwalking, tics, tremor, and suicidal thoughts and behavior (including suicide). The FDA states these events have been reported in adult, adolescent, and pediatric patients with and without a previous history of psychiatric disorder, and some occurred even after the drug was stopped. Watch children especially closely. Stop montelukast and call the doctor right away for any new or unusual mood or behavior change, and get emergency help for thoughts of suicide.

Beyond mood and behavior changes, seek immediate care for signs of a severe allergic or skin reaction. MedlinePlus says to call your doctor or get emergency help for "difficulty breathing or swallowing; swelling of the face, throat, tongue, lips, or eyes; hoarseness; itching; rash; hives," or "blistering, peeling, or shedding skin." For any thoughts of harming yourself, call 988 (the Suicide and Crisis Lifeline) or 911. This is not a complete list of serious effects; see the FDA label.

That is a decision for you and your prescriber, and the FDA has shifted the benefit-risk balance for allergies. Because of the neuropsychiatric risk, the FDA now advises that for allergic rhinitis, montelukast "should be reserved for those who are not treated effectively with or cannot tolerate other allergy medicines" such as antihistamines or nasal steroids. The warning weighs differently for asthma, where treatment options may be more limited. Do not stop a prescribed medicine on your own without talking to your doctor first, especially if it controls your asthma.

Neuropsychiatric side effects can appear at any point. The FDA notes events have been reported "mostly during Singulair treatment, but some were reported after discontinuation," so a new mood or behavior change can emerge shortly after starting, later in treatment, or even after stopping. Common effects like headache or stomach pain are usually short-lived. Montelukast is not a drug that requires a slow taper to stop safely, but do not discontinue it on your own if it controls your asthma; abruptly losing asthma control can be dangerous, so contact your prescriber to plan any change.

Montelukast is FDA-approved for the long-term control of asthma in adults and children, prevention of exercise-induced bronchoconstriction, and relief of symptoms from seasonal and year-round allergic rhinitis (hay fever). It's a leukotriene receptor antagonist — it blocks inflammatory chemicals called leukotrienes. It's a daily controller taken to prevent symptoms, not a rescue medicine for a sudden asthma attack.

Yes. In 2020 the FDA added a boxed warning — its strongest — for serious mental-health side effects, including agitation, depression, sleep problems, and suicidal thoughts or actions. Because of this, the FDA advises that for allergic rhinitis, montelukast generally be reserved for people who can't tolerate or don't respond to other allergy treatments like antihistamines or nasal steroids. Discuss the benefits and risks with your prescriber, and report any mood or behavior changes.