Five RCTs were included (n=287). Three of the studies were classified as high quality (score ≥3). The quality scores ranged from 0 to 4. Concomitant interventions for the management of acute bacterial exacerbation of chronic bronchitis were not standardised in the trials.
Treatment success: Based on intention to treat data (five RCTs, n=262), there was no statistically significant difference between semisynthetic penicillin and trimethoprim based regimens in treatment success (odds ratio 1.68, 95% CI: 0.91 to 3.09).
Adverse events: Based on intention to treat data from three RCTs (n=186 for adverse events in general and n=179 for withdrawals due to adverse events), there was no statistically significant difference between intervention and comparator for number of adverse events in general (odds ratio 0.37, 95% CI: 0.11 to 1.24) and for withdrawal due to adverse events (odds ratio 0.27, 95% CI: 0.07 to 1.03). In two studies there was no statistically significant difference between the two groups in number of episodes of diarrhoea or skin rash.
Mortality: Based on one trial of 37 patients, there was no statistically significant difference in mortality between amoxicillin (6%) and trimethoprim (11%).