Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

  • Review
  • Intervention




Individuals with chronic bronchitis or chronic obstructive pulmonary disease (COPD) may suffer recurrent exacerbations with an increase in volume and/or purulence of sputum. Because of the personal and healthcare costs associated with exacerbations, any therapy that reduces the number of exacerbations is useful. There is a marked difference between countries in terms of prescribing of mucolytics depending on whether or not they are perceived to be effective.


To assess the effects of oral mucolytics in adults with stable chronic bronchitis or COPD.

Search methods

We searched the Cochrane Airways Group Specialised Register and reference lists of articles on eight separate occasions, the most recent being in September 2008.

Selection criteria

Randomised trials that compared oral mucolytic therapy with placebo for at least two months in adults with chronic bronchitis or COPD. We excluded studies of people with asthma and cystic fibrosis.

Data collection and analysis

One review author extracted data. We contacted study authors and drug companies for missing information.

Main results

Twenty-eight trials involving 7042 participants were included. Compared with placebo, there was a significant reduction in the number of exacerbations per patient with oral mucolytics (weighted mean difference (WMD) -0.04 per month, 95% confidence interval -0.05 to -0.03). Using a weighted annualised rate of exacerbations in the control patients of 2.4 per year, this is a 21% reduction. The number of days of disability also fell (WMD -0.56, 95% confidence interval (CI) -0.77 to -0.35). One recent study has shown that the benefit may apply only to patients not already receiving inhaled corticosteroids. The number of patients who remained exacerbation-free was greater in the mucolytic group (odds ratio (OR) 1.93 (95% CI 1.71 to 2.17)). There is no strong evidence of improvement in lung function and treatment is not associated with any increase in adverse effects. Patients on mucolytics may be less likely to be hospitalised during the study period.

Authors' conclusions

In participants with chronic bronchitis or COPD, treatment with mucolytics was associated with a small reduction in acute exacerbations and a reduction in total number of days of disability. Benefit may be greater in individuals who have frequent or prolonged exacerbations, or those who are repeatedly admitted to hospital with exacerbations with COPD. Mucolytics should be considered for use, through the winter months at least, in patients with moderate or severe COPD in whom inhaled corticosteroids (ICS) are not prescribed.








我們檢索了the Cochrane Airways Group Specialised Register 和八次不同檢索中參考文獻目錄的文章。其最近的一次檢索是於2008年9月進行。






總共涵括了28個試驗,包含了7042名受試者。與安慰劑相比,使用口服化痰劑有顯著減少每名患者病情惡化的次數(加權均差(WMD)−0.04每月95%信賴區間 −0.05至−0.03)。以對照組病情惡化的加權年率為2.4年為基礎,使用口服化痰劑減少了21%。行動不便的天數也減少了(WMD0.56,95%信賴區間(CI)−0.77到0.35)。最近的一項研究顯示,可能只對尚未使用過吸入式皮質類固醇的病人有益。無病情惡化的病人數目於使用化痰劑的組別仍然也是增加(odds ratio(OR)1.93(95%CI為 1.71至2.17))。沒有強有力的證據顯示肺功能有改善和治療不與任何副作用的增加相關。使用化痰劑的患者於研究期間顯示可能較不需要住院。





此翻譯計畫由臺灣國家衛生研究院(National Health Research Institutes, Taiwan)統籌。



Plain language summary

Mucolytic agents for chronic bronchitis or chronic obstructive pulmonary disease

Twenty-eight trials with 7042 participants were included in this review of trials. The evidence suggests that if patients take the medicines regularly through the winter months this could result in a 21% reduction in the number of exacerbations (approximately 0.5 fewer per year), especially in people not already taking inhaled corticosteroids. There is considerable variation between the results of different studies in this review that is not fully explained. These medicines do not alter the loss of lung function in COPD, but they are very safe and well tolerated.