Randomized Prospective Study Comparing Erythromycin, Amoxicillin, and Clindamycin for the Treatment of Chlamydia trachomatis in Pregnancy

Objective: The purpose of this study was to compare the efficacy and side effects of erythromycin, amoxicillin, and clindamycin in eradicating Chlamydia trachomatis from the lower genital tract of pregnant women. Methods: A total of 174 women at <36 weeks gestation with positive cervical cultures for C. trachomatis were enrolled. Patients were assigned in a randomized prospective fashion to either erythromycin (500 mg q.i.d, for 7 days), amoxicillin (500 mg t.i.d, for 7 days), or clindamycin (600 mg t.i.d, for 10 days). Six women elected not to participate and 8 patients were lost to follow-up, leaving 53 patients in the erythromycin group, 55 patients in the amoxicillin group, and 52 patients in the clindamycin group. All sexual partners of the enrolled women were offered doxycycline (100 mg b.i.d. for 7 days) and patients were instructed to use barrier contraception until treatment was complete. Results: All 3 medications were effective agents for the treatment of antenatal C. trachomatis infection with treatment efficacies of 96%, 94%, and 98% for the erythromycin, amoxicillin, and clindamycin groups, respectively. When the antibiotic groups were compared, no statistically significant differences were noted in intolerance. However, the differences in the incidence of gastrointestinal symptoms between erythromycin and amoxicillin and/or clindamycin were significant (P < 0.05). Conclusions: These findings suggest that 1) all 3 antibiotic regimens are efficacious, 2) erythromycin has a higher incidence of side effects, and 3) amoxicillin or clindamycin are reasonable alternatives for the treatment of C. trachomatis in pregnant patients unable to tolerate erythromycin.