What are the side effects of Singular (montelukast)?

From the Guidelines

Singulair (montelukast) can cause several side effects, including headache, upper respiratory infection symptoms, cough, fever, abdominal pain, diarrhea, and mild skin rash, as well as more concerning neuropsychiatric effects such as agitation, aggression, anxiety, depression, sleep disturbances, suicidal thoughts, and hallucinations. These side effects are based on the medication's mechanism of blocking leukotrienes, chemicals involved in inflammation, which helps control asthma and allergy symptoms, but may affect brain function in some individuals, explaining the neuropsychiatric effects 1. Some of the key side effects to be aware of include:

• Common side effects: headache, upper respiratory infection symptoms, cough, fever, abdominal pain, diarrhea, and mild skin rash
• Neuropsychiatric side effects: agitation, aggression, anxiety, depression, sleep disturbances, suicidal thoughts, and hallucinations
• Rare but serious side effects: allergic reactions (hives, difficulty breathing, swelling), liver problems (yellowing of skin/eyes, dark urine), and Churg-Strauss syndrome (severe asthma with flu-like symptoms, numbness in limbs, and heart complications) It is essential for patients to contact their healthcare provider immediately if they experience mood or behavior changes while taking this medication, and should never stop taking it suddenly without medical guidance 1. Additionally, montelukast has been compared to other asthma treatments in terms of efficacy and safety, with studies showing that it can be an effective alternative therapy for mild persistent asthma in patients who are unable or unwilling to use inhaled corticosteroids 1. However, the most recent and highest quality study should be prioritized when making a definitive recommendation, and patients should be closely monitored for any potential side effects while taking this medication.

From the FDA Drug Label

The side effects of SINGULAIR are usually mild, and generally did not cause patients to stop taking their medicine. The side effects in patients treated with SINGULAIR were similar in type and frequency to side effects in patients who were given a placebo (a pill containing no medicine) common side effects that have happened with SINGULAIR include: increased bleeding tendency allergic reactions [including swelling of the face, lips, tongue, and/or throat (which may cause trouble breathing or swallowing), hives and itching] drowsiness, pins and needles/numbness, seizures (convulsions or fits) palpitations nose bleed diarrhea, indigestion, inflammation of the pancreas, nausea, vomiting hepatitis bruising joint pain, muscle aches and muscle cramps swelling Behavior and mood-related changes have been reported: agitation including aggressive behavior or hostility, bad/vivid dreams, depression, feeling anxious, hallucinations (seeing things that are not there), irritability, restlessness, sleep walking, suicidal thoughts and actions (including suicide), tremor, trouble sleeping

The side effects of Singular (montelukast) include:

• Allergic reactions
• Increased bleeding tendency
• Drowsiness
• Seizures
• Palpitations
• Nose bleed
• Diarrhea
• Indigestion
• Inflammation of the pancreas
• Nausea
• Vomiting
• Hepatitis
• Bruising
• Joint pain
• Muscle aches
• Muscle cramps
• Swelling
• Behavior and mood-related changes, such as:

• Agitation
• Aggressive behavior
• Bad/vivid dreams
• Depression
• Feeling anxious
• Hallucinations
• Irritability
• Restlessness
• Sleep walking
• Suicidal thoughts and actions
• Tremor
• Trouble sleeping 2

From the Research

Side Effects of Singular (Montelukast)

The side effects of Singular (montelukast) have been studied in various research papers. Some of the common side effects reported include:

• Abdominal pain 3, 4, 5, 6
• Neuropsychiatric reactions such as insomnia, hyperactivity, and nightmares 4, 5, 6, 7
• Sleep disturbances, including sleep interruption and decreased sleep 5
• Agitation 5, 6
• Pain 5
• Hyperactivity 4, 5
• Headaches 6
• Depression 6
• Aggression 6
• Hallucinations 7
• Attention problems 7
• Disorientation, anxiety, stress reactions, and somatic symptoms 7

Rare Side Effects

Some rare side effects reported include:

• Allergic granulomatous angiitis 6
• Limb paresthesia 4
• Paraesthesia in extremities 4

Demographic Variations

The side effects of montelukast may vary across different demographics. For example:

• Children aged 4-9 years are more likely to experience adverse drug reactions 5
• Men prescribed montelukast may be at a higher risk of hallucinations and attention problems 7