Montelukast side effects: what 83,390 FDA adverse event reports show
Drug class
Not stated in label
Who reports
83,390 reports · 65% serious · 4,014 with death outcome · 68% female
Used for
Montelukast sodium tablets are a leukotriene receptor antagonist indicated for: • Prophylaxis and chronic treatment of asthma in patients 15 years of age and older (1.1). • Acute prevention of exercise-induced bronchoconstriction (EIB) in patients 15 years of age and older (1.2).
What it is
Montelukast sodium USP, the active ingredient in montelukast sodium tablets, USP is a selective and orally active leukotriene receptor antagonist that inhibits the cysteinyl leukotriene CysLT 1 receptor.
Boxed warning
SERIOUS NEUROPSYCHIATRIC EVENTS Serious neuropsychiatric (NP) events have been reported with the use of montelukast sodium. The types of events reported were highly variable, and included, but were not limited to, agitation, aggression, depression, sleep disturbances, suicidal thoughts and behavior (including suicide).
Causality screen of the 40 strongest signals
What the badges mean
- Labeled adverse reaction The exact term appears in the label's warnings or adverse-reactions sections: a known, expected effect. The FAERS signal confirms the label rather than discovering anything.
- Labeled (related wording) The label describes this effect under different wording (e.g. 'neutropenia' for 'neutrophil count decreased'). Treated as known.
- Likely indication confounding The term appears in the label's indications: reports probably describe the disease being treated (or its progression), not a drug effect. Classic confounding by indication.
- Reporting / coding artifact An administrative, monitoring or exposure term (product issue, off-label use, 'test normal', overdose...). Not a biological reaction; a high PRR here reflects how reports are coded.
- Lab value / disease marker A laboratory result, investigation or disease-activity marker (antibody positive, CRP abnormal, swollen joint count) not described in the label. These usually mirror the monitored disease or testing protocol rather than a drug effect; not screened further.
- Not in label — unassessed Not found in the label text, not an artifact pattern. This is a genuine candidate for a formal causality assessment (Bradford Hill / WHO-UMC); it has NOT had one here.
Strongest disproportionality signals
Flagged terms (PRR ≥ 2, χ² ≥ 4, n ≥ 10), ranked by PRR; infinite PRRs (no comparator reports) excluded. The EBGM column is a second, shrinkage-based estimate (MGPS) with its 5th percentile EB05 and the BCPNN IC025; a pair flagged by PRR alone is marked PRR-only and should be read as fragile. The strata column recomputes the PRR on serious reports only (and, for the 300 most-reported drugs, adjusted for age band), and flags pairs whose reports are unusually skewed by sex or come mostly from consumers. Each row also shows the PRR against the other drugs of the same FDA class, which removes most confounding by the condition being treated, and a calibrated p-value: on validation, known non-causes average an ROR of about 2, so significance is judged against that empirical null (✓ = p < 0.05 after calibration). 1,186 further terms are in the interactive explorer. Reaction links open the term's cross-drug page.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Right atrial hypertrophy | 59 | 285.7 196.4–415.6ROR 285.9 · calibrated p 7e-11 ✓ | 127.6 EB05 102.5 · IC025 +5.5 3/3 methods agree | Not in label — unassessed | serious n=59 · ♀ 0% (drug 68%) | not reported in cached trials |
| Sensitisation | 284 | 148.6 128.3–172.1ROR 149.1 · calibrated p 6e-9 ✓ | 92.6 EB05 83.9 · IC025 +6.1 3/3 methods agree | Not in label — unassessed | serious n=284 · ♀ 100% (drug 68%) | not reported in cached trials |
| Ejection fraction | 216 | 147.8 124.9–174.9ROR 148.2 · calibrated p 6e-9 ✓ | 92.1 EB05 82.2 · IC025 +6.0 3/3 methods agree | Not in label — unassessed | serious n=216 · ♀ 100% (drug 68%) | not reported in cached trials |
| Total lung capacity abnormal | 135 | 138.4 112.1–170.8ROR 138.6 · calibrated p 1e-8 ✓ | 88.0 EB05 76.2 · IC025 +5.8 3/3 methods agree | Not in label — unassessed | serious n=132 · ♀ 0% (drug 68%) | not reported in cached trials |
| Pulmonary vasculitis | 162 | 111.1 92.3–133.8ROR 111.4 · calibrated p 6e-8 ✓ | 76.3 EB05 66.9 · IC025 +5.7 3/3 methods agree | Labeled (related wording) related wording | serious n=162 · ♀ 0% (drug 68%) | not reported in cached trials |
| Eosinophilic granulomatosis with polyangiitis | 505 | 83.8 75.8–92.7ROR 84.3 · calibrated p 4e-7 ✓ | 62.7 EB05 58.2 · IC025 +5.7 3/3 methods agree | Not in label — unassessed | serious n=505 · ♀ 47% (drug 68%) | not reported in cached trials |
| Total lung capacity increased | 61 | 72.1 54.2–95.9ROR 72.1 · calibrated p 2e-6 ✓ | 55.1 EB05 44.5 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious n=61 · ♀ 100% (drug 68%) · 100% clinician | not reported in cached trials |
| Mite allergy | 138 | 69.3 57.4–83.7ROR 69.4 · calibrated p 2e-6 ✓ | 53.9 EB05 46.8 · IC025 +5.2 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=134 · ♀ 0% (drug 68%) | not reported in cached trials |
| Spirometry abnormal | 126 | 68.5 56.3–83.5ROR 68.6 · calibrated p 2e-6 ✓ | 53.5 EB05 46.1 · IC025 +5.2 3/3 methods agree | Lab value / disease marker | serious n=124 · ♀ 0% (drug 68%) | not reported in cached trials |
| Capillaritis | 55 | 64.7 48.1–87.0ROR 64.7 · calibrated p 4e-6 ✓ | 50.6 EB05 40.4 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=55 · ♀ 0% (drug 68%) · 100% clinician | not reported in cached trials |
| Asthma-chronic obstructive pulmonary disease overlap syndrome | 99 | 58.9 47.3–73.4ROR 59.0 · calibrated p 6e-6 ✓ | 47.4 EB05 40.0 · IC025 +4.9 3/3 methods agree | Labeled (related wording) related wording | serious n=98 · ♀ 42% (drug 68%) | not reported in cached trials |
| Obsessive-compulsive symptom | 67 | 55.9 42.9–72.9ROR 55.9 · calibrated p 9e-6 ✓ | 45.2 EB05 36.8 · IC025 +4.7 3/3 methods agree | Labeled adverse reaction exact term | serious n=62 · ♀ 0% (drug 68%) · 100% consumer | not reported in cached trials |
| Defiant behaviour | 55 | 55.4 41.4–74.3ROR 55.5 · calibrated p 1e-5 ✓ | 44.8 EB05 35.7 · IC025 +4.6 3/3 methods agree | Not in label — unassessed | serious n=54 · ♀ 0% (drug 68%) · 100% consumer | not reported in cached trials |
| Polycystic ovaries | 274 | 53.0 46.5–60.4ROR 53.2 · calibrated p 1e-5 ✓ | 43.7 EB05 39.5 · IC025 +5.1 3/3 methods agree | Not in label — unassessed | serious n=272 · ♀ 100% (drug 68%) | not reported in cached trials |
| Human rhinovirus test positive | 64 | 52.0 39.7–68.1ROR 52.0 · calibrated p 1e-5 ✓ | 42.6 EB05 34.6 · IC025 +4.6 3/3 methods agree | Lab value / disease marker | serious n=63 · ♀ 100% (drug 68%) · 100% clinician | not reported in cached trials |
| Bronchopulmonary aspergillosis allergic | 147 | 47.9 40.1–57.1ROR 48.0 · calibrated p 2e-5 ✓ | 40.1 EB05 34.9 · IC025 +4.9 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=145 | not reported in cached trials |
| Epidural lipomatosis | 55 | 47.0 35.2–62.7ROR 47.0 · calibrated p 3e-5 ✓ | 39.2 EB05 31.2 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=54 · ♀ 0% (drug 68%) · 100% clinician | not reported in cached trials |
| Vital capacity decreased | 69 | 45.3 35.1–58.6ROR 45.4 · calibrated p 3e-5 ✓ | 38.1 EB05 31.1 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | serious n=68 · ♀ 0% (drug 68%) | not reported in cached trials |
| Mycotic allergy | 126 | 44.1 36.5–53.3ROR 44.1 · calibrated p 3e-5 ✓ | 37.4 EB05 32.2 · IC025 +4.7 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=125 · ♀ 0% (drug 68%) | not reported in cached trials |
| Dust allergy | 143 | 43.7 36.6–52.1ROR 43.7 · calibrated p 3e-5 ✓ | 37.1 EB05 32.3 · IC025 +4.8 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=141 · ♀ 0% (drug 68%) | not reported in cached trials |
| Chronic spontaneous urticaria | 157 | 41.7 35.2–49.3ROR 41.7 · calibrated p 5e-5 ✓ | 35.6 EB05 31.2 · IC025 +4.7 3/3 methods agree | Not in label — unassessed | serious n=148 | not reported in cached trials |
| Sleep terror | 568 | 39.1 35.8–42.8ROR 39.4 · calibrated p 6e-5 ✓ | 33.9 EB05 31.6 · IC025 +4.9 3/3 methods agree | Not in label — unassessed | serious n=543 · ♀ 37% (drug 68%) | not reported in cached trials |
| Temperature regulation disorder | 292 | 38.7 34.2–43.7ROR 38.8 · calibrated p 7e-5 ✓ | 33.5 EB05 30.4 · IC025 +4.8 3/3 methods agree | Not in label — unassessed | serious n=291 · ♀ 100% (drug 68%) | not reported in cached trials |
| Antineutrophil cytoplasmic antibody positive | 92 | 36.2 29.1–45.1ROR 36.3 · calibrated p 1e-4 ✓ | 31.5 EB05 26.5 · IC025 +4.4 3/3 methods agree | Lab value / disease marker | serious n=92 · ♀ 0% (drug 68%) · 100% clinician | not reported in cached trials |
| Bronchial wall thickening | 90 | 35.5 28.5–44.3ROR 35.5 · calibrated p 1e-4 ✓ | 31.0 EB05 26.0 · IC025 +4.4 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=90 · ♀ 0% (drug 68%) | not reported in cached trials |
| Forced expiratory volume decreased | 349 | 35.2 31.4–39.3ROR 35.3 · calibrated p 1e-4 ✓ | 30.9 EB05 28.2 · IC025 +4.7 3/3 methods agree | Lab value / disease marker | serious n=347 · ♀ 38% (drug 68%) | not reported in cached trials |
| Neuropsychological symptoms | 70 | 34.4 26.8–44.2ROR 34.5 · calibrated p 2e-4 ✓ | 30.1 EB05 24.7 · IC025 +4.3 3/3 methods agree | Likely indication confounding shares a disease stem with the indications wording | serious n=70 · 100% clinician | not reported in cached trials |
| Rhinitis allergic | 503 | 32.0 29.2–35.1ROR 32.2 · calibrated p 2e-4 ✓ | 28.4 EB05 26.4 · IC025 +4.6 3/3 methods agree | Likely indication confounding term in indications; also in warnings | serious n=478 · ♀ 88% (drug 68%) | not reported in cached trials |
| Pneumonia haemophilus | 55 | 31.9 24.1–42.2ROR 31.9 · calibrated p 2e-4 ✓ | 28.1 EB05 22.4 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=56 · ♀ 100% (drug 68%) · 100% clinician | not reported in cached trials |
| Blood immunoglobulin e increased | 270 | 31.2 27.5–35.4ROR 31.3 · calibrated p 2e-4 ✓ | 27.8 EB05 25.1 · IC025 +4.5 3/3 methods agree | Lab value / disease marker | serious n=259 | not reported in cached trials |
| Body tinea | 62 | 30.9 23.8–40.3ROR 31.0 · calibrated p 3e-4 ✓ | 27.4 EB05 22.1 · IC025 +4.1 3/3 methods agree | Not in label — unassessed | serious n=56 · ♀ 100% (drug 68%) · 100% clinician | not reported in cached trials |
| Respiratory symptom | 297 | 29.7 26.4–33.5ROR 29.8 · calibrated p 3e-4 ✓ | 26.6 EB05 24.2 · IC025 +4.5 3/3 methods agree | Labeled (related wording) related wording | serious n=293 · ♀ 42% (drug 68%) | not reported in cached trials |
| Reversible airways obstruction | 54 | 29.4 22.2–38.9ROR 29.4 · calibrated p 4e-4 ✓ | 26.1 EB05 20.8 · IC025 +4.0 3/3 methods agree | Not in label — unassessed | serious n=54 · ♀ 0% (drug 68%) · 100% consumer | not reported in cached trials |
| Nasal oedema | 184 | 28.7 24.6–33.4ROR 28.7 · calibrated p 4e-4 ✓ | 25.7 EB05 22.7 · IC025 +4.4 3/3 methods agree | Labeled (related wording) related wording | serious n=182 · ♀ 100% (drug 68%) | not reported in cached trials |
| Mast cell activation syndrome | 130 | 27.3 22.8–32.7ROR 27.3 · calibrated p 5e-4 ✓ | 24.6 EB05 21.2 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=127 · ♀ 100% (drug 68%) | not reported in cached trials |
| Obstructive airways disorder | 1,085 | 27.0 25.4–28.7ROR 27.3 · calibrated p 4e-4 ✓ | 24.4 EB05 23.2 · IC025 +4.5 3/3 methods agree | Not in label — unassessed | age-adj. PRR 24.6 · serious PRR 22.5 | not reported in cached trials |
| Asthmatic crisis | 354 | 26.9 24.1–30.0ROR 27.0 · calibrated p 5e-4 ✓ | 24.3 EB05 22.2 · IC025 +4.4 3/3 methods agree | Not in label — unassessed | serious n=354 | not reported in cached trials |
| Neuritis | 148 | 26.7 22.5–31.6ROR 26.7 · calibrated p 5e-4 ✓ | 24.1 EB05 21.0 · IC025 +4.2 3/3 methods agree | Not in label — unassessed | serious n=146 · ♀ 0% (drug 68%) | not reported in cached trials |
| Pulmonary function test abnormal | 150 | 26.6 22.5–31.5ROR 26.7 · calibrated p 5e-4 ✓ | 24.1 EB05 21.0 · IC025 +4.2 3/3 methods agree | Reporting / coding artifact | serious n=146 · ♀ 26% (drug 68%) | not reported in cached trials |
| Respiratory syncytial virus test positive | 66 | 25.9 20.1–33.3ROR 25.9 · calibrated p 7e-4 ✓ | 23.4 EB05 19.0 · IC025 +3.9 3/3 methods agree | Lab value / disease marker | serious n=65 · ♀ 100% (drug 68%) · 100% clinician | not reported in cached trials |
Clinical concept groups
MedDRA splits one clinical problem across several terms (e.g. "neutropenia", "neutrophil count decreased", "agranulocytosis"), which dilutes term-level signals. These rows count reports with any term in a concept group (an exact union, not a sum), compared with all other drugs. Groups are hand-built and listed in the methods.
| Concept | Reports | PRR 95% CI | Reading |
|---|---|---|---|
| Depression | 3,321 | 3.02.9–3.1 | signal |
| Anaphylaxis / angioedema | 1,427 | 2.92.7–3.0 | signal |
| Serious infection | 6,948 | 2.32.2–2.3 | signal |
| Interstitial lung disease | 699 | 1.81.7–2.0 | raised |
| Suicidality | 1,705 | 1.71.7–1.8 | raised |
| Opportunistic infection | 852 | 1.61.5–1.7 | raised |
| Fall / fracture | 2,349 | 1.61.5–1.6 | raised |
| Tendon disorder | 219 | 1.41.3–1.7 | raised |
| Arrhythmia / qt | 1,010 | 1.31.2–1.4 | raised |
| Venous thromboembolism | 1,074 | 1.21.2–1.3 | raised |
| Kidney injury | 2,192 | 1.21.2–1.3 | raised |
| Thrombocytopenia | 1,014 | 1.21.1–1.2 | raised |
| Heart failure | 814 | 1.11.1–1.2 | raised |
| Hyponatraemia | 355 | 1.11.0–1.2 | no difference |
| Liver injury | 1,305 | 1.11.0–1.1 | raised |
| Pancreatitis | 329 | 1.00.9–1.1 | no difference |
Trial evidence (ClinicalTrials.gov)
✓ Trial adverse-event data found on ClinicalTrials.gov
Largest completed trials with posted results that list Montelukast as a study intervention. The right-hand column of the signal table shows whether each FAERS term was also recorded in these trials, with a real denominator (0 of 40 signal terms matched).
- NCT00092118 — The Clinical Effects of Montelukast in Patients With Perennial Allergic Rhinitis (0476-265) (N=1992, PHASE3; 5 AE terms posted; arms: Placebo; Montelukast 10 mg)
Caveats: trial populations, doses and follow-up differ from the reporting population; AE terms are sponsor-coded and matched here by wording; absence from a trial list means the term was not reported above the sponsor's frequency threshold, not that it cannot occur.
Most frequently reported reactions
By raw co-report count, regardless of disproportionality. Common terms here are often the illness itself or generic outcomes.
| Reaction | Reports | PRR 95% CI · ROR · χ²/p | EBGM EB05 · IC025 | Label screen | Serious-only & strata | Trial cross-check |
|---|---|---|---|---|---|---|
| Dyspnoea (shortness of breath) | 8,238 | 3.7 3.6–3.8ROR 4.0 · calibrated p 0.378 | 3.7 EB05 3.6 · IC025 +1.8 3/3 methods agree | Not in label — unassessed | age-adj. PRR 3.4 · serious PRR 3.7 | not reported in cached trials |
| Asthma | 7,885 | 19.0 18.5–19.4ROR 20.8 · calibrated p 0.002 ✓ | 17.7 EB05 17.4 · IC025 +4.1 3/3 methods agree | Labeled — boxed warning exact term | age-adj. PRR 19.5 · serious PRR 18.5 | NCT00092118: 1/1,002 (0.1%) on Montelukast (serious AE) |
| Drug ineffective (drug did not work) | 6,320 | 1.2 1.2–1.2ROR 1.2 · calibrated p 0.456 | 1.2 EB05 1.2 · IC025 +0.2 | Reporting / coding artifact | age-adj. PRR 1.4 · serious PRR 1.8 | not reported in cached trials |
| Fatigue (tiredness) | 5,836 | 1.9 1.8–1.9ROR 2.0 · calibrated p 0.923 | 1.9 EB05 1.8 · IC025 +0.9 | Labeled adverse reaction exact term | age-adj. PRR 1.8 · serious PRR 2.1 | not reported in cached trials |
| Headache | 5,123 | 2.1 2.0–2.1ROR 2.1 · calibrated p 0.985 | 2.1 EB05 2.0 · IC025 +1.0 3/3 methods agree | Labeled adverse reaction exact term | age-adj. PRR 2.0 · serious PRR 2.6 | not reported in cached trials |
| Cough | 4,980 | 4.5 4.4–4.7ROR 4.8 · calibrated p 0.262 | 4.5 EB05 4.4 · IC025 +2.1 3/3 methods agree | Labeled adverse reaction exact term | age-adj. PRR 4.2 · serious PRR 5.1 | not reported in cached trials |
| Nausea | 4,498 | 1.4 1.4–1.5ROR 1.5 · calibrated p 0.615 | 1.4 EB05 1.4 · IC025 +0.5 | Labeled adverse reaction exact term | age-adj. PRR 1.3 · serious PRR 1.6 | not reported in cached trials |
| Off label use (used outside approved label) | 4,224 | 1.2 1.2–1.3ROR 1.2 · calibrated p 0.465 | 1.2 EB05 1.2 · IC025 +0.2 | Reporting / coding artifact | age-adj. PRR 1.1 · serious PRR 1.4 | not reported in cached trials |
| Pneumonia (lung infection) | 4,185 | 3.3 3.2–3.4ROR 3.4 · calibrated p 0.509 | 3.3 EB05 3.2 · IC025 +1.7 3/3 methods agree | Labeled (related wording) related wording | age-adj. PRR 3.1 · serious PRR 3.0 | not reported in cached trials |
| Pain | 3,873 | 1.6 1.5–1.6ROR 1.6 · calibrated p 0.715 | 1.6 EB05 1.5 · IC025 +0.6 | Labeled adverse reaction exact term | age-adj. PRR 1.8 · serious PRR 1.6 | not reported in cached trials |
| Diarrhoea (diarrhea) | 3,670 | 1.4 1.4–1.5ROR 1.5 · calibrated p 0.613 | 1.4 EB05 1.4 · IC025 +0.5 | Labeled adverse reaction exact term | age-adj. PRR 1.4 · serious PRR 1.4 | not reported in cached trials |
| Anxiety | 3,574 | 3.2 3.1–3.3ROR 3.3 · calibrated p 0.544 | 3.1 EB05 3.1 · IC025 +1.6 3/3 methods agree | Not in label — unassessed | age-adj. PRR 3.6 · serious PRR 3.6 | NCT00092118: 1/1,002 (0.1%) on Montelukast (serious AE) |
| Wheezing | 3,517 | 15.8 15.3–16.4ROR 16.5 · calibrated p 0.005 ✓ | 14.9 EB05 14.5 · IC025 +3.8 3/3 methods agree | Not in label — unassessed | age-adj. PRR 15.4 · serious PRR 16.4 | not reported in cached trials |
| Malaise (feeling unwell) | 3,147 | 1.8 1.7–1.9ROR 1.8 · calibrated p 0.851 | 1.8 EB05 1.7 · IC025 +0.8 | Not in label — unassessed | age-adj. PRR 1.9 · serious PRR 2.1 | not reported in cached trials |
| Dizziness | 3,141 | 1.6 1.5–1.6ROR 1.6 · calibrated p 0.714 | 1.6 EB05 1.5 · IC025 +0.6 | Labeled adverse reaction exact term | age-adj. PRR 1.5 · serious PRR 1.7 | not reported in cached trials |
Unlabeled candidate signals
These flagged terms were not found in the FDA label text and do not match an artifact pattern. They are the pairs that would merit a structured assessment (temporality, dose-response, biological plausibility, consistency across databases, trial or cohort evidence). The screen has not done that; string-matching misses label wording, and a strong PRR can still be stimulated reporting, co-medication, or the disease itself.
- Right atrial hypertrophy — n=59, PRR 285.7
- Sensitisation — n=284, PRR 148.6
- Ejection fraction — n=216, PRR 147.8
- Total lung capacity abnormal — n=135, PRR 138.4
- Eosinophilic granulomatosis with polyangiitis — n=505, PRR 83.8
- Total lung capacity increased — n=61, PRR 72.1
- Capillaritis — n=55, PRR 64.7
- Defiant behaviour — n=55, PRR 55.4
- Polycystic ovaries — n=274, PRR 53.0
- Epidural lipomatosis — n=55, PRR 47.0
✓ A hand-written Bradford Hill causality assessment exists for this drug: Montelukast ↔ Neuropsychiatric events.
Want to assess one of these properly? The runbook describes the Bradford Hill / trial-evidence workflow used on the assessment page, and handoff_top1000_signals.csv lists the strongest unassessed pairs across all drugs.
Common questions
What are the most reported side effects of Montelukast?
In FDA FAERS, the most frequently co-reported reaction terms for Montelukast are dyspnoea, asthma, fatigue, headache, cough, nausea. These are report counts, not rates: FAERS has no denominator, reporting is voluntary and uneven, and a term can be reported because of the illness being treated rather than the drug.
Does Montelukast have an FDA boxed warning?
Yes. The current FDA label carries a boxed warning: SERIOUS NEUROPSYCHIATRIC EVENTS Serious neuropsychiatric (NP) events have been reported with the use of montelukast sodium. The types of events reported were highly variable, and included, but were not limited to, agitation, aggression, depression, sleep disturbances, suicidal thoughts and behavior (including suicide).
Do FAERS signals prove that Montelukast causes these side effects?
No. A disproportionality signal (PRR, ROR) means a reaction is reported more often with this drug than with others in the database. That can reflect a real effect, but also the disease being treated, stimulated reporting after news or litigation, co-medications, or how reports are coded. Causality needs temporality, dose-response, biological plausibility, consistency across data sources and, ideally, trial or cohort evidence. This page screens each term against the FDA label and ClinicalTrials.gov results; it does not establish causation.
Sources & methods
- FDA label via openFDA (set ID 4fe3c0d4-94ff-43ca-9d24-54676fe593fe, effective 20210626; matched on
openfda.generic_name.exact:"MONTELUKAST" AND openfda.product_type:"HUMAN PRESCRIPTION DRUG") - Bayesian shrinkage measures computed offline over all 1,317,300 cached pairs: BCPNN information component (IC, with Norén closed-form IC025) and MGPS empirical-Bayes geometric mean (EBGM, EB05) with a two-component gamma prior fitted by maximum marginal likelihood (α₁=0.57, β₁=0.02, α₂=1.42, β₂=0.70, w=0.17); unstratified
- FAERS pair statistics from the OpenPV build of 2026-09-14 (openFDA
count=aggregation, fieldpatient.drug.openfda.generic_name.exact, 1,226 reaction terms, min 3 co-reports); PRR/ROR with 95% CI, chi-square with Yates correction - Serious-only and stratified counts (serious:1, patient.patientsex, primarysource.qualification) from openFDA count queries; serious-only PRR uses the drug serious report total and the term global serious total (N_serious=11,882,979); strata shown only when n ≥ 20
- Seriousness and sex counts from openFDA
count=serious,patient.patientsex,seriousnessdeath - ClinicalTrials.gov API v2 (query
MONTELUKAST, results-bearing studies sorted by enrollment)
Page generated 2026-10-14. Label and PubChem text are retrieved automatically and may lag the current label; always check the current prescribing information. OpenPV is a beta research tool of the Open Source Medicine Foundation.