Abstract: There are no new trials to include in this review update. Previously, four studies with a total of 224 participants were included; one was performed exclusively in children and three in adolescents or adults. One using an antitussive had no extractable pneumonia-specific data. Three different mucolytics (bromhexine, ambroxol, neltenexine) were used in the remaining studies, of which only two had extractable data. They demonstrated no significant difference for the primary outcome of 'not cured or not improved' for mucolytics. A secondary outcome of 'not cured' was reduced (odds ratio (OR) for children 0.36, 95% confidence interval (CI) 0.16 to 0.77; number needed to treat to benefit (NNTB) at day 10 = 5 (95% CI 3 to 16) and OR 0.32 for adults (95% CI 0.13 to 0.75); NNTB at day 10 = 5 (95% CI 3 to 19)). In a post hoc analysis combining data for children and adults, again there was no difference in the primary outcome of 'not cured or not improved' (OR 0.85, 95% CI 0.40 to 1.80) although mucolytics reduced the secondary outcome 'not cured' (OR 0.34, 95% CI 0.19 to 0.60; NNTB 4, 95% CI 3 to 8). The risk of bias was low or unclear. There is insufficient evidence to decide whether OTC medications for cough associated with acute pneumonia are beneficial. Mucolytics may be beneficial but there is insufficient evidence to recommend them as an adjunctive treatment for acute pneumonia. This leaves only theoretical recommendations that OTC medications containing codeine and antihistamines should not be used in young children.

Plain-language summary: In this review we found four studies with a total of 224 participants that were suitable for inclusion; one was performed exclusively in children and three in adolescents or adults. However, data could only be obtained from two studies; both studies used mucolytics (ambroxol and bromhexine) in conjunction with antibiotics. Combining these two studies, the rate of cure or improvement in cough of people who received mucolytics was similar to those who did not. However, in the secondary analysis, children who received a mucolytic were more likely to be cured of cough (the number needed to treat to benefit (NNTB) at day 10 was 5 for children and 4 for adults). There were no reported increased adverse events in the treatment group. The range of possible adverse events associated with OTC medications for cough is wide and includes minimal adverse events (such as with the use of honey) to serious adverse events, such as altered heart rate patterns, drowsiness and death in young children. The studies included in this review did not report any detectable increase in adverse events. There were no obvious biases in the studies. This review has substantial limitations due to the unavailability of data from studies. Also there are no studies of other common OTC medications used for cough, such as antihistamines and antitussives. Thus, there is insufficient evidence to draw any definitive conclusions on the role of OTC medications taken as an additional treatment for cough associated with acute pneumonia. Mucolytics may be beneficial but the lack of consistent evidence precludes recommending the routine use of mucolytics as an addition in the treatment of troublesome cough associated with pneumonia in children or adults. The evidence is current to January 2014.