Four RCTs involving a total of 551 patients (277 treated with amoxicillin and 274 treated with erythromycin) were included.
The pooled RR for the treatment success of amoxicillin compared with erythromycin was 1.11 (95% CI: 1.05, 1.18, p<0.01). However, treatment efficacy (defined as the number of patients who completed their course of antibiotics with negative test of cure) was 225 out of 243 (92.6%) in the amoxicillin group and 206 out of 217 (94.9%) in the erythromycin group (RR 1.00, 95% CI: 0.97, 1.02, p=0.70). This suggests that when taken appropriately, amoxicillin and erythromycin are equally efficacious, but amoxicillin is more effective than erythromycin in leading to a completion of therapy with a subsequent negative test of cure.
The pooled RR for amoxicillin, compared with erythromycin, for all reported gastrointestinal side-effects was 0.29 (95% CI: 0.20, 0.42, p<0.01). For gastrointestinal side-effects that resulted in the discontinuation of therapy, the pooled RR was 0.14 (95% CI: 0.06, 0.36, p<0.01).
The chi-squared test of heterogeneity for treatment effects among trials was not significant for treatment success (p=0.18), reported gastrointestinal side-effects (p=0.62) or number of patients who discontinued therapy (p=0.81).