Single-dose azithromycin for Chlamydia in pregnant women

To assess the efficacy and occurrence of severe side effects associated with the use of a single dose of azithromycin in the treatment of Chlamydia trachomatis in pregnant women.

Patients and their sexual partners were randomized into three treatment groups: both the patient and her sexual partner received a single dose of azithromycin (group 1); the patient was given a standard course of erythromycin, while her partner was given a standard course of tetracycline (group 2); and the patient was given a single dose of azithromycin with the sexual partner given a standard course of tetracycline (group 3). Group 3 was included in order to assess the relative efficacy of tetracycline with respect to the use of azithromycin among patients and to indirectly assess possible patient reinfection by sexual partners.

With respect to the cure rate, 4.5% of study participants given azithromycin has positive cultures vs. 21.1% of patients given erythromycin or tetracycline (P = .018). With respect to side effects severe enough to warrant a change in medication, 7.4% of patients receiving azithromycin reported suffering such side effects vs. 38.8% of patients given erythromycin (P = .02). Among sexual partners, 28.6% given tetracycline reported severe side effects vs. none of those given azithromycin (P = .03).

Azithromycin in the treatment of C trachomatis in pregnant women substantially improved the cure rates while substantially reducing the occurrence of severe side effects associated with the use of a standard course of erythromycin. Since both tetracycline and erythromycin are known to be effective against C trachomatis infection, the improved efficacy of azithromycin is probably due to noncompliance with the multidose, multiday regimen associated with the use of these two antibiotics.