Doxycycline more effective than azithromycin for chlamydia

Trial finds doxycycline slightly more effective, but researchers not entirely convinced of its superiority.

Study finds that azithromycin is not as clinically effective as doxycycline for chlamydia. In the image, human pap smear showing chlamydia

Standard treatment for chlamydia is a single dose of azithromycin or a week’s course of doxycycline twice daily. However, evidence suggests that azithromycin may not be as effective as doxycycline. 

To establish efficacy, US researchers randomly assigned adolescents with urogenital Chlamydia trachomatis infection to azithromycin (n=284) or doxycycline (n=283) (155 adolescents completed the study in each group). The participants were residents at youth correctional facilities, which made the chances of reinfection low, say the researchers. 

The efficacy of doxycycline was 100%, compared with 97% for azithromycin. The results meant that azithromycin was not deemed as clinically effective as doxycycline. 

However, writing in The
New England Journal of Medicine (online, 24 December 2015)[1]
, the researchers say that the exceptional efficacy of doxycycline may be offset by poorer adherence to the week-long regimen in real-world settings.


[1] Geisler WM, Uniyal A, Lee JY et al. Azithromycin versus doxycycline for urogenital Chlamydia trachomatis infection. New England Journal of Medicine 2015;373:2512–2521. doi: 10.1056/NEJMoa1502599

Last updated
Clinical Pharmacist, CP, February 2016, Vol 8, No 2;8(2):DOI:10.1211/PJ.2016.20200441

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