A meta-analysis assessing azithromycin (1 g once) versus doxycycline (100 mg twice daily for 7 days) for genital chlamydial infections included 12 RCTs with a total of 1543 males and nonpregnant females. Cure rates were 97% for azithromycin and 98% for doxycycline. Adverse events occurred in 25% and 23% of patients treated with azithromycin and doxycycline, respectively. After pooling of the data, differences in efficacy and risk were computed. The efficacy and risk of adverse events between the two drugs were not statistically significant.
A topic in Clinical Evidence summarizes the results of one systematic review (search date 2001, 12 blinded and unblinded RCTs, 1543 people). Azithromycin 1 g as a single dose was as effective as doxycycline 100 mg twice daily for 7 days (cure rates for azithromycin 81–100%, doxycycline 92–100%, pooled efficacy difference +0.008, 95% CI -0.007 to +0.022).