Montelukast,
does it really help with Shortened symptoms and duration of adult postinfectious cough?
research showsMontelukast is rated D because a 276-person publicly funded trial found no benefit for postinfectious cough. Placebo LCQ improvement was already 3.6 points at two weeks and 5.9 at four weeks, showing substantial natural recovery.
ads claimAn asthma indication is expanded to a cough lingering after infection, but the direct trial showed no added benefit beyond natural recovery.
Useful facts when choosing a product
- The trial randomized 276 and analyzed 275 by intention to treat; 25% had laboratory-confirmed pertussis.
- Of 259 with two-week data, 192 chose another two weeks of treatment.
What the research actually shows
Wang randomized 276 and analyzed 275. LCQ differences were -0.9 (-1.7 to -0.04) at two weeks and -0.5 (-1.5 to 0.6) at four weeks; placebo improved by 3.6 and 5.9 points. The intervals exclude the 1.3-point LCQ MCID. In contrast, Dong and colleagues reviewed 14 low-quality trials with 1,372 participants that pointed positive, although poor methods prevented a firm conclusion. Results therefore conflict, giving R0 rather than RX. verdict 1630, which is C with 45 points, verdict 1727, which is D with 25 points, and verdict 1447, which is C with 52 points, were not transferred. The FDA boxed warning affects safety only.
Why this is classified as D (30)
P, R0, I2, E0, B1, and C1 derive D with 30 points because conflicting evidence is not repeated refutation.
Counterpoint. Worsening cough, dyspnea, hemoptysis, fever, or prolonged symptoms require reassessment rather than assuming benign postinfectious cough.
Rejudgment record. Cross-check applied — The high-quality null Wang trial conflicts with the positive direction of 14 low-quality trials, giving R0 rather than RX
| Endpoint | P | Patient-reported treatment goal - the symptom is the goal |
| Replication | R0 | Trials conflict in direction |
| Independence | I2 | Decisive evidence is publicly or non-profit funded |
| Effect size | E0 | Null |
| Precision | C1 | The confidence interval excludes meaningful benefit |
The scoring table and the verdict agree (D).
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Cough-related quality of life at two weeks | D | The result was 0.9 points worse than placebo and the primary endpoint failed. |
| Faster cough recovery at four weeks | D | Improvement was 5.2 versus 5.9 points and did not favor treatment. |
| Cough improvement in laboratory-confirmed pertussis | D | No subgroup signal was used to overturn the null overall analysis. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Wang K et al. 2014 | Four-week randomized double-blind placebo-controlled trial | 1 | Public funding from the United Kingdom NIHR School for Primary Care Research | Change in Leicester Cough Questionnaire at two and four weeks | Difference -0.9 (-1.7 to -0.04) at two weeks and -0.5 (-1.5 to 0.6) at four weeks; missed the 1.3 MCID and the primary endpoint failed | Only key direct randomized trial |
| Raj AA et al. 2009 | Prospective validation study of the LCQ minimum important difference | 52 | Academic research with no manufacturer sponsorship reported | Correspondence between LCQ change and patient global ratings of change | The minimum important difference for total LCQ was 1.3 points | MCID source |
| Dong S et al. 2015 | Systematic review of randomized trials | 1,372 | Academic review; included trials had major bias | Cough relief, frequency, severity, and quality of life | Positive direction, but poor methods prevented a firm conclusion | Evidence for conflicting R0 |
Receipt — 3 References
All 3 cited sources were verified for existence at the original page (as of 2026-07-24).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-07-24 · Corrections: none
Cite this verdict
[Chamgap] Montelukast x shorter adult postinfectious cough — Evidence Grade D·30. 3 cited sources checked. Source: https://chamgap.com/en/verdicts/immunity/montelukast-adult-postinfectious-cough-duration/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.