What is the black‑box warning for montelukast (Singulair)?

Montelukast Black Box Warning

The FDA issued a black box warning for montelukast in March 2020 regarding serious neuropsychiatric events, including agitation, depression, sleep disturbances, suicidal thoughts and actions, and other behavioral changes 1.

Warning Details

The boxed warning specifically mandates:

• Immediate discontinuation if neuropsychiatric symptoms occur 1
• Active monitoring for neuropsychiatric symptoms in all patients taking montelukast 1
• Thorough discussion of benefits and risks with patients and caregivers before initiating therapy 1

Critical Prescribing Restriction for Allergic Rhinitis

For allergic rhinitis specifically, montelukast should be reserved ONLY for patients who have inadequate response or intolerance to alternative therapies 1. This restriction reflects the FDA's determination that the benefits may not outweigh the neuropsychiatric risks when treating this condition, given the availability of safer alternatives like intranasal corticosteroids and antihistamines.

Asthma Indication Unchanged

Importantly, the asthma indication was not restricted in the same manner 2. The FDA concluded that the benefit-risk profile remained favorable for asthma management, where montelukast provides meaningful therapeutic value 2.

Neuropsychiatric Events Documented

The warning encompasses a broad spectrum of mental health effects:

• Agitation and aggression
• Depression and anxiety
• Sleep disturbances (insomnia, nightmares, sleepwalking)
• Suicidal thoughts and actions
• Attention and behavior problems
• Confusion and psychotic-like symptoms 1

Clinical Context and Controversy

The FDA's decision followed years of postmarketing surveillance beginning in 2007, multiple safety reviews, analysis of claims data through the Sentinel Distributed Database, and a public Advisory Committee meeting in September 2019 2.

However, recent high-quality observational data challenges the magnitude of this risk. A 2025 Swedish nationwide cohort study of 74,291 children found no association between montelukast use and neuropsychiatric adverse events compared to long-acting beta-agonists (weighted HR 0.99,95% CI 0.84-1.16) 3. This study specifically examined anxiety, depression, sleep disorders, suicidal actions, and behavioral disturbances—finding no increased risk in any category 3.

Practical Management Algorithm

Before prescribing:

1. For allergic rhinitis: Confirm patient has failed or cannot tolerate intranasal corticosteroids AND oral antihistamines
2. Screen for pre-existing psychiatric conditions or family history of mental health disorders
3. Document detailed discussion of neuropsychiatric risks with patient/caregiver
4. Obtain informed consent acknowledging the black box warning

During treatment:

1. Schedule follow-up within 2-4 weeks of initiation
2. Actively query about mood changes, sleep disturbances, behavioral changes, or suicidal ideation at every visit
3. Educate patients/caregivers to report ANY neuropsychiatric symptoms immediately
4. Stop montelukast immediately if any concerning symptoms emerge—do not wait to assess severity 1

Common Pitfall

Do not assume the warning applies equally across all indications. The FDA explicitly maintained the asthma indication without restriction while limiting allergic rhinitis use 2. This nuanced approach reflects different benefit-risk calculations for different conditions.