Montelukast
| Evidence Level: L2 | Predicted Indications: 2 |
Table of Contents
Montelukast: Bronchitis
One-Sentence Summary
Montelukast is a cysteinyl leukotriene receptor antagonist that is marketed in Canada in many single-ingredient products. The TxGNN model predicts it may be useful for bronchitis, with a prediction score of 0.9995. The data compiled for this report include 17 clinical trials and 20 publications on this topic, but the indexed term mostly reflects bronchiolitis (infant viral bronchiolitis and bronchiolitis obliterans), and results in infants are mixed or negative.
Quick Overview
| Item | Content |
|---|---|
| Original Indication | Not recorded in the local data |
| Predicted New Indication | Bronchitis |
| TxGNN Prediction Score | 0.9995 |
| Evidence Level | L2 |
| Canada Market Status | Marketed (marketed DINs on record: at least 19; dormant: 1) |
| Number of DINs | at least 20 |
| Recommended Decision | Hold |
Why is This Prediction Reasonable?
Detailed mechanism of action data is not available in the data compiled for this report. Montelukast is known as a cysteinyl leukotriene (CysLT1) receptor antagonist. Blocking this receptor may reduce airway inflammation, mucus production and bronchial hyperreactivity.
Leukotrienes are released during viral airway infection, such as RSV bronchiolitis, and are also implicated in the fibro-inflammatory process of bronchiolitis obliterans after transplantation. Preclinical rat data support this second link.
An important caveat: the indexed disease term “bronchitis” maps largely to bronchiolitis, which includes infant viral bronchiolitis and bronchiolitis obliterans syndrome. These are distinct clinical entities from bronchitis in the usual sense. Clinical results in infant populations are mixed or negative. One small placebo-controlled trial exists in nonasthmatic eosinophilic bronchitis, which is closer to the predicted disease.
Clinical Trial Evidence
| Trial Number | Phase | Status | Enrollment | Key Findings |
|---|---|---|---|---|
| NCT00076973 | Phase 3 | Completed | 1125 | Two doses of montelukast vs placebo for respiratory symptoms of RSV bronchiolitis in children 3–24 months |
| NCT00863317 | N/A | Completed | 141 | Randomized, double-blind, placebo-controlled trial of daily montelukast on illness duration in infants with first-time viral bronchiolitis |
| NCT01370187 | N/A | Completed | 146 | Montelukast for acute bronchiolitis and post-bronchiolitis wheezing in infants 3–12 months |
| NCT00524693 | N/A | Completed | 51 | Double-blind placebo-controlled trial in acute RSV bronchiolitis, with clinical and cytokine outcomes |
| NCT01121016 | Phase 4 | Unknown | 63 | Add-on montelukast to inhaled budesonide in nonasthmatic eosinophilic bronchitis (cough) |
| NCT04613180 | Phase 4 | Unknown | 100 | Montelukast for treatment and prevention of recurrent obstructive bronchitis in children |
| NCT00656058 | Phase 2 | Completed | 25 | Single-agent montelukast for bronchiolitis obliterans after stem cell transplantation; small and uncontrolled |
| NCT01211509 | Phase 4 | Completed | 30 | Placebo-controlled trial of montelukast for bronchiolitis obliterans syndrome after lung transplantation |
| NCT01307462 | Phase 2 | Completed | 36 | Fluticasone, azithromycin and montelukast combination for bronchiolitis obliterans after stem cell transplant; montelukast’s own contribution cannot be isolated |
| NCT00394160 | Phase 2 | Completed | 12 | Safety, tolerability and plasma concentration of montelukast granules in infants 1 to <3 months with bronchiolitis |
Literature Evidence
| PMID | Year | Type | Journal | Key Findings |
|---|---|---|---|---|
| 25773054 | 2015 | Systematic review (Cochrane) | Cochrane Database Syst Rev | Leukotriene inhibitors such as montelukast for bronchiolitis in infants and young children |
| 24118637 | 2014 | Systematic review | Pediatr Allergy Immunol | Montelukast’s efficacy for preventing post-bronchiolitis wheezing |
| 25563311 | 2015 | Clinical study | Chin Med J | Add-on montelukast to budesonide in nonasthmatic eosinophilic bronchitis: effects on airway inflammation, cough and quality of life |
| 29704475 | 2018 | Guideline/Expert panel | Chest | Chronic cough after acute viral bronchiolitis in children |
| 38504551 | 2024 | Review | Ther Adv Respir Dis | Therapeutic potential of montelukast in bronchiolitis obliterans syndrome after lung and stem-cell transplantation |
| 38485149 | 2024 | Guideline | Eur Respir J | ERS/EBMT guidelines on treatment of pulmonary chronic graft-versus-host disease in adults |
| 28545478 | 2017 | Preclinical (animal) | J Cardiothorac Surg | LTB4 and montelukast in transplantation-related bronchiolitis obliterans in rats |
| 14766663 | 2004 | Commentary | Am J Respir Crit Care Med | Montelukast in RSV bronchiolitis |
| 28662986 | 2017 | Systematic review | J Heart Lung Transplant | Therapy options for chronic lung allograft dysfunction–bronchiolitis obliterans syndrome |
| 40926299 | 2025 | Consensus statement | Br J Haematol | Taiwan consensus on pulmonary chronic graft-versus-host disease |
Canada Market Information
| DIN | Product Name | Dosage Form | Approved Indication |
|---|---|---|---|
| 02238216 | SINGULAIR | Not available | Not available |
| 02445735 | BIO-MONTELUKAST | Not available | Not available |
| 02382458 | MONTELUKAST | Not available | Not available |
| 02514877 | JAMP MONTELUKAST CHEWABLE TABLETS | Not available | Not available |
| 02422875 | AURO-MONTELUKAST CHEWABLE TABLET | Not available | Not available |
The list shows five of the licences found. The records may be partial, and the approved indication text is not recorded in the local data.
Safety Considerations
- Drug Interactions: The interaction screen returned 100 entries. Moderate-level interactions include dexamethasone, metronidazole, miconazole, nateglinide, nitisinone and troglitazone. Several others (for example calcitriol, phentermine, pantoprazole, glimepiride, metformin, omeprazole) are listed with unknown severity.
For warnings and contraindications, please refer to the package insert.
Conclusion and Next Steps
Decision: Hold
Rationale: Montelukast has a plausible leukotriene-based mechanism and is widely marketed in Canada, and many trials exist. However, the predicted term mostly corresponds to bronchiolitis, and the larger infant trials have mixed or negative results. The evidence directly addressing bronchitis itself is limited to a small trial in eosinophilic bronchitis. Several relevant trials are small, uncontrolled, or test montelukast only as part of a combination.
To proceed, the following is needed:
- A clear definition of the target condition (bronchitis versus bronchiolitis versus eosinophilic bronchitis)
- Review of the results of the larger placebo-controlled trials (for example NCT00076973) and the Cochrane review for efficacy conclusions
- Mechanism of action data and package insert warnings and contraindications
- A focused controlled study in a well-defined bronchitis population
Disclaimer
This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.