Nine studies (1,435 participants) were included in the review. The mean quality score was 59 per cent (range 33 to 76).
Clinical cure: Loperamide plus antibiotic was associated with an increased probability of cure at 24 hours (odds ratio was 2.58, 95% CI: 1.84 to 3.61; six RCTs). Although there was no statistical evidence of heterogeneity (p=0.20), the Forest plot indicated that the study in Thailand (with a high prevalence of Campylobacter) showed no benefit of adjunct loperamide when all the other studies did. The benefit of adjunct loperamide was also evident at 48 hours (odds ratio was 2.15, 95% CI: 1.50 to 3.09; six RCTs), but was not statistically significant at 72 hours (odds ratio was 1.40, 95% CI: 0.91 to 2.14; five RCTs).
Time to last unformed stool: Loperamide plus antibiotic was associated with a significantly reduced time to last unformed stool in all five studies that reported this outcome. The time to last unformed stool ranged from two to 23 hours less in the intervention group. There was significant (p<0.001) statistical heterogeneity between groups.
There were no significant differences in treatment failures between the loperamide plus antibiotic and antibiotic only groups, and no adverse events associated with loperamide.
Subgroup analyses: showed no effect of age, sex, study quality, regimen, antibiotic type, country of study, traveler characteristics or pre-treatment duration of symptoms.