Tools for Practice

#329 Coughing up the evidence: Bronchodilators or inhaled steroids for post-infectious cough

Do bronchodilators or inhaled corticosteroids (ICS) improve post-infectious cough in adults without asthma?

Data is very limited with only two ICS randomized controlled trials (RCTs) (163 patients) and one bronchodilator RCT (92 patients). For adults, post-infectious cough scores may improve ~50% on placebo and ~5-10% more with ICS over 2 weeks. Ipratropium/salbutamol may resolve cough in more patients than placebo at day 10 (69% versus 37%) but most patients (>80%, regardless of treatment) will have cough resolution by day 20.

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  • Differences statistically significant unless noted.
  • ICS versus placebo:
    • Four systematic reviews of treatments for persistent cough (4-9 RCTs, 335-750 patients): Interpretation limited by inclusion of RCTs with acute (<3 weeks)1,2 and chronic (>8 weeks)2,3 cough, and multiple drug classes.4  
      • Most useful systematic review2 (2 RCTs, 163 patients), mostly subacute cough (3-8 weeks):
        • ICS 0.42 (standard mean difference) better than placebo. In clinical terms, placebo improved cough scores at ~2 weeks by ~50-56% and ICS improves ~2-13% more.
        • Largest RCT5 (133 patients) also reported:
          • Additional outcomes (days off work, nocturnal awakenings, adverse effects): No difference.
          • Proportion of non-smokers with >50% cough improvement: 81% versus 54% (placebo), number needed to treat (NNT)=4.
            • No improvement among smokers.
          • Limitations: Not all patients had post-infectious cough; study industry funded.
        • Bronchodilators versus placebo:
          • One RCT6 of 92 patients (cough duration 3-4 weeks): Combination of nebulized salbutamol/ipratropium versus placebo.
            • Proportion with ongoing cough at day 10: 37% versus 69% placebo, NNT=3.
            • No difference at day 20 (both >80% resolved).
            • Limitations: Small studies; non-validated cough scores; multiple outcomes.
  • Post-infectious cough is a cough persisting 3-8 weeks after an acute respiratory illness.7
  • One RCT8 compared beclomethasone and placebo in 72 patients with prolonged acute cough (10 days-3 weeks), so likely not true post-infectious (subacute) cough.
    • ICS improved 3 of 6 outcomes over placebo on device-measured cough, but no difference in patient-reported symptoms.
  • Guidelines suggest considering a trial of inhaled ipratropium or, if refractory, inhaled corticosteroids.9
  • RCTs above did not include patients with COVID-19.

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  • Emelie Braschi MD CCFP PhD
  • G. Michael Allan MD CCFP
  • Samantha Moe PharmD

1. El-Gohary M, Hay AD, Coventry P, et al. Family Practice 2013; 30: 492-500.

2. Lee SE, Lee JH, Kim HJ, et al. Allergy Asthma Immunol Res 2019; 11(6): 856-70.

3. Johnstone KJ, Chang AB, Fong KM, et al. Cochrane Database Syst Rev. 2013 Mar 28; (3):CD009305.

4. Speich B, Thomer A, Aghlmandi S, et al. Br J Gen Pract. 2018; 68(675):e694-e702.

5. Ponsioen BP, Hop WCJ, Vermue NA, et al. Eur Respir J 2005; 25 (1): 147-52.

6. Zanasi A, Lecchi M, Del Forno M, et al. Pulm Pharmacol Ther 2014; 29: 224-32.

7. Irwin RS, French CL, Chang AB, et al. Chest 2018; 153(10): 196-209.

8. Gillissen A, Richter A, Oster H. J Physiol Pharmacol 2007; 58 (Suppl 5 Pt 1):223-32.

9. Irwin RS, Baumann MH, Bolser DC, et al. Chest 2006; 129(1 Suppl):1S-23S.

Authors do not have any conflicts of interest to declare.