HealthDay News — Azithromycin is not noninferior to doxycycline for treatment of urogenital chlamydia infection among adolescents; however, the efficacy of both types of treatment is high, according to a study published in the New England Journal of Medicine.

William M. Geisler, MD, MPH, from the University of Alabama at Birmingham, and colleagues conducted a randomized trial comparing oral azithromycin with doxycycline for urogenital chlamydia infection among adolescents in youth correctional facilities. The authors assessed the noninferiority of 1 g azithromycin (one dose) with 100 mg doxycycline twice daily for seven days. Participants were randomly allocated to receive azithromycin (284 participants) or doxycycline (283 participants). The per-protocol population comprised 155 patients in each treatment group.

The researchers found that treatment failure did not occur in any patients in the doxycycline group, compared with five patients (3.2%) in the azithromycin group. The observed difference in treatment failure was 3.2%, with an upper boundary of the 90% confidence internal of 5.9%; this exceeded the prespecified absolute 5% cut-off for establishing noninferiority of azithromycin.

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“In the context of a closed population receiving directly observed treatment for urogenital chlamydia infection, the efficacy of azithromycin was 97%, and the efficacy of doxycycline was 100%,” the authors write. “The noninferiority of azithromycin was not established in this setting.”

Geisler disclosed financial ties to ActivBiotics Pharma.


1. Geisler WM, Uniyal A, Lee JY, et al. Azithromycin versus doxycycline for urogenital Chlamydia trachomatis Infection. N Engl J Med. 2015;373:2512-2521.