Does Montelukast Make You Sleepy? Singulair and Sleep

More Medication Articles

Does Montelukast Make You Sleepy? Singulair and Sleep

By Your Health Magazine Health Information Team

You take Singulair in the evening, then notice yourself yawning earlier than usual—or struggling to feel alert the next morning. It is reasonable to wonder: Does montelukast make you sleepy, and is that why the medication is often taken at night?

The short answer is that montelukast can be associated with drowsiness in some people, but sleepiness is not considered one of its most common effects. Research has not consistently shown that routine doses cause more daytime sleepiness than a placebo. However, individual reactions vary, and montelukast can affect sleep in several ways, including unusual dreams, nightmares, insomnia, sleepwalking, and disrupted sleep.

What Is Montelukast?

Montelukast is the generic name for Singulair. It is a leukotriene receptor antagonist, meaning it blocks inflammatory substances called leukotrienes. These substances contribute to airway swelling, mucus production, and allergy symptoms.

The medication may be prescribed for long-term asthma management, prevention of exercise-induced airway narrowing, or certain cases of allergic rhinitis. It controls symptoms but does not cure asthma or allergies, and it is not a rescue treatment for a sudden asthma attack.

Unlike some older antihistamines, montelukast is not designed to produce sedation. It is also not a sleeping medication. If you become tired after taking it, the effect may be an individual medication reaction, the result of disturbed sleep, or something unrelated to montelukast.

How Montelukast May Affect Sleep

People sometimes use “sleepy” to describe several different experiences. Montelukast’s possible effects include true drowsiness, fatigue, difficulty waking, or reduced alertness. In other cases, a person may feel tired during the day because the medication appears to be affecting sleep quality at night.

Reported sleep-related effects include:

• Daytime drowsiness or somnolence
• Difficulty falling asleep or staying asleep
• Vivid or unusual dreams
• Nightmares or night terrors
• Restless or interrupted sleep
• Sleepwalking

These reactions do not happen to everyone. Available studies have also produced mixed findings. Some observational research has found an association between montelukast and sleep disorders, particularly among adults, while other studies and clinical trials have not found a meaningful increase in overall neuropsychiatric events compared with placebo.

Postmarketing reports are important for detecting uncommon reactions, but they cannot show exactly how frequently a symptom occurs or prove that the medication caused every reported event. Even so, a new sleep problem that begins after starting montelukast deserves attention.

Why Is Singulair Often Taken at Night?

Evening use does not necessarily mean that Singulair is sedating. When montelukast is prescribed for asthma, product instructions commonly place it in the evening as part of consistent symptom control. Timing for allergic rhinitis may be more flexible, depending on the prescription and the person’s treatment plan.

Do not change your medication schedule solely because it makes you tired without first discussing the issue with a healthcare professional. A pharmacist or prescribing clinician can review why you take montelukast, when your symptoms occur, and whether another time or treatment may be more appropriate.

For additional context, read about taking montelukast at night and how timing may relate to treatment.

Could Something Else Be Causing the Sleepiness?

Feeling sleepy while taking montelukast does not automatically mean the medication is responsible. Asthma and allergies can interfere with sleep by causing congestion, coughing, wheezing, itching, or nighttime breathing symptoms. Poorly controlled symptoms may leave you exhausted even if you spend enough hours in bed.

Other possible contributors include:

• Sedating antihistamines or nighttime cold medicines
• Prescription pain, anxiety, or sleep medications
• Alcohol or cannabis use
• Sleep apnea or another sleep disorder
• Viral illness, anemia, thyroid disease, or depression
• Stress, irregular sleep hours, or insufficient sleep

Reviewing when the tiredness started can help. Consider whether it appeared after beginning montelukast, changing another medication, developing worse allergy symptoms, or experiencing new sleep disturbances. A brief record of medication times, sleep quality, dreams, and daytime alertness may provide useful information for your clinician.

The Boxed Warning and Mental Health Changes

Montelukast carries an FDA boxed warning about serious neuropsychiatric events. Reported reactions include agitation, aggressive behavior, anxiety, depression, confusion, attention or memory problems, hallucinations, abnormal dreams, insomnia, sleepwalking, and suicidal thoughts or actions.

These effects have been reported in people with and without a previous mental health condition. Some occurred during treatment, while others were reported after the medication was discontinued. Because of this warning, montelukast is generally reserved for allergic rhinitis when other appropriate treatments have not worked or cannot be tolerated.

Patients and caregivers should understand these risks and monitor for changes in sleep, mood, thinking, or behavior. The MedlinePlus drug information resource provides reliable consumer guidance about prescription medications and their safety warnings.

Everyday Safety If You Feel Drowsy

Until you know how montelukast affects you, be cautious with activities that require sustained alertness. If you feel unusually sleepy, avoid driving, operating machinery, climbing ladders, or performing hazardous work. Combining several substances that cause sedation may worsen impairment.

For children, caregivers may notice changes that the child cannot clearly describe, such as difficulty waking, unusual irritability, nightmares, declining concentration, restlessness, or changes in school behavior. These observations should be shared promptly with the child’s pediatrician or prescribing specialist.

When to Seek Care

Contact the prescribing clinician or a pharmacist if sleepiness is persistent, interferes with driving, school, work, or daily activities, or begins soon after montelukast is started. Evaluation is also appropriate for new nightmares, insomnia, sleepwalking, mood changes, confusion, or unusual behavior.

Seek immediate professional help for suicidal thoughts or actions, hallucinations, severe agitation, aggressive behavior, or other sudden and concerning mental health changes. Emergency care is also needed for serious allergic symptoms, such as facial or throat swelling, difficulty breathing, or fainting.

If asthma symptoms suddenly become severe, use the rescue treatment specified in the asthma action plan and obtain urgent care when needed. Montelukast should not be relied upon to stop an acute asthma attack.

The Bottom Line

Montelukast may make some people sleepy, but it is not generally considered a sedating medication, and drowsiness is not among its most common effects. Sleep disruption—including nightmares, insomnia, and sleepwalking—may also produce daytime fatigue. Because montelukast carries a boxed warning for potentially serious changes in mood, behavior, and sleep, new symptoms should not be ignored.

A healthcare professional can help determine whether the tiredness is likely related to Singulair, uncontrolled asthma or allergies, another medication, or a separate health issue. Do not make medication changes on your own; instead, discuss the symptom and the treatment’s benefits and risks with the clinician who manages your asthma or allergies.