Randomized Clinical Trial of Azithromycin vs. Erythromycin for the Treatment of Chlamydia Cervicitis in Pregnancy

Objective: The purpose of this study was to prospectively test the null hypothesis that there is no difference in the clinical effectiveness of azithromycin and erythromycin for the treatment of chlamydia cervicitis in pregnancy. Methods: All antepartum obstetrical patients underwent routine screening for chlamydia cervicitis using a DNA probe assay (Gen-Probe Pace, San Diego, CA). Women who tested positive for chlamydia cervicitis were prospectively randomized to receive either azithromycin 1 g orally at enrollment, or erythromycin 500 mg orally 4 times a day for 7 days. Sexual partners were referred to the county health department for evaluation and treatment. A test of cure was repeated in 2 weeks. Results were analyzed by chi-square analysis and Fisher's exact test when indicated. Results: One hundred forty women tested positive for chlamydia cervicitis and agreed to randomization. There were 4 (6.2%) treatment failures in the azithromycin group and 18 (27.7%) in the erythromycin group (P = 0.005). Gastrointestinal side effects were reported by 42 (65.5%) of the women taking erythromycin, but only 12 (19.4%) of those taking azithromycin (P < 0.002). Gastrointestinal side effects and resultant noncompliance were significantly related to treatment failure with erythromycin. Conclusions: The findings of this study support the conclusion that a single dose of azithromycin is a significantly more effective and better tolerated treatment regimen for chlamydia cervicitis in pregnancy than erythromycin which is currently recommended.