Doxycycline or Azithromycin for Rectal Chlamydia Infection?

Rectal chlamydia is the most common bacterial sexually transmitted infection (STI) in men who have sex with men (MSM). CDC guidelines recommend doxycycline or azithromycin as first-line agents for treating rectal chlamydia infection. Observational data suggest that doxycycline is more effective than azithromycin. To determine the difference in efficacy between the two agents, investigators conducted a randomized, double-blinded, placebo-controlled study comparing the efficacy of the two agents in treating rectal chlamydia infection in MSM with the primary endpoint of microbiologic cure at 4 weeks.

When the prespecified halting rules for difference in efficacy were met, 177 participants had been enrolled (mean age, 34; 15% co-infected with HI…