Silverman NS, Sullivan M, Hochman M, Womack M, Jungkind DL
A randomized, prospective trial comparing amoxicillin and erythromycin for
the treatment of Chlamydia trachomatis in pregnancy.
Am J Obstet Gynecol 1994 Mar;170(3):829-32

OBJECTIVE: Our purpose was to evaluate the efficacy of amoxicillin as an
alternative therapy to erythromycin for the treatment of cervical chlamydial
infections during pregnancy. STUDY DESIGN: A randomized, prospective trial
of two treatment regimens for Chlamydia trachomatis was performed in a
cohort of pregnant women enrolled for care in an inner-city,
university-based prenatal clinic, with an alternate-therapy crossover arm
for primary treatment failures. Pregnant women diagnosed with chlamydial
infection by McCoy cell culture of cervical swabs were assigned to receive
either 500 mg of amoxicillin three times daily or 500 mg of erythromycin
four times daily for 7 days. Patients' partners were treated with
doxycycline. Compliance information was obtained by a standardized
questionnaire at a posttherapy follow-up visit. Patients with positive
follow-up cultures were crossed over into the alternate treatment arm and
recultured at a later visit. RESULTS: During the study period 74 women
consented to participate in this trial; 36 were treated with amoxicillin and
38 with erythromycin. Initial cure rates of 82.3% (28/34) for the
amoxicillin group and 84.6% (27/32) for erythromycin were obtained before
crossover (p = 0.91); four patients in each group were lost to follow-up.
Overall cure rates after crossover were 84.6% (33/39) for amoxicillin and
84.2% (32/38) for erythromycin (p = 0.83). In the amoxicillin group 12.8% of
patients reported side effects compared with 31.6% treated with erythromycin
(p = 0.09), although seven erythromycin-treated patients compared with none
of those in the amoxicillin arm stopped therapy because of side effects
(p =0.02). CONCLUSION: Amoxicillin offers a reasonable alternative to
erythromycin for the treatment of Chlamydia trachomatis in pregnancy, on the
basis of both cure rates and patient compliance.

Alary M, Joly JR, Moutquin JM, Mondor M, Boucher M, Fortier A, Pinault JJ,
Paris G, Carrier S, Chamberland H, et al
Randomised comparison of amoxycillin and erythromycin in treatment of
genital chlamydial infection in pregnancy [see comments]
Lancet 1994 Nov 26;344(8935):1461-5

Erythromycin, the standard treatment for chlamydial infection in pregnant
women, commonly causes side-effects, which limits its efficacy. In a
randomised, double-blind study, we compared amoxycillin with erythromycin in
this setting. 210 pregnant women with Chlamydia trachomatis infection were
randomly assigned 7 days' treatment with amoxycillin (500 mg three times
daily) or erythromycin (500 mg four times daily). Control cultures were
obtained 21 days after treatment, during late pregnancy, and from the infant
within a week of birth. Treatment was judged a failure if any post-treatment
culture was positive or if the patient had to stop therapy because of severe
side-effects. 11 women (5.2%) were lost to follow-up. 1 (of 100)
amoxycillin-treated women had to stop treatment because of severe
side-effects compared with 12 (of 99) erythromycin-treated women (p =
0.002). 1 woman in the amoxycillin group had a positive culture at the
third-trimester examination. No positive post-treatment culture was found in
the erythromycin group. Severe gastrointestinal side-effects were more
common in women who received erythromycin (31 vs 6%, p < 0.001). The overall
failure rate was therefore 2% in the amoxycillin group and 12% in the
erythromycin group (p = 0.005). These results suggest that amoxycillin is an
acceptable alternative to erythromycin for C trachomatis infection in
pregnant women.