Objective: To evaluate recent publications on efficacy of single-dose azithromycin and 7-day doxycycline when treating Chlamydia trachomatis.
Data sources: A literature search of MEDLINE, EMBASE, PubMed, and Cochrane library was conducted (1990 to June 13, 2021) using the terms: Chlamydia trachomatis, genital chlamydia, rectal chlamydia, extragenital chlamydia, azithromycin, doxycycline, and treatment guidelines. ClinicalTrials.gov was searched to identify ongoing trials.
Study selection and data extraction: English language studies, including controlled studies, retrospective analyses, systematic reviews, meta-analyses, and case reports, reporting microbiological or clinical outcomes in adolescents and adults were considered.
Data synthesis: Systemic reviews and meta-analyses of randomized trials reported azithromycin efficacy of 96% to 97% in genital chlamydia. However, reports of treatment failure have emerged, especially among symptomatic males, with an increased risk of microbiological failure after azithromycin than doxycycline (relative risk = 2.45; 95% CI = 1.36-4.41). Retrospective analyses and prospective observational cohort studies reported lower efficacy range following azithromycin than doxycycline (74%-87% vs 92%-100%, respectively) in rectal chlamydia. First randomized controlled trial comparing azithromycin and doxycycline reported significantly higher microbiological cure following doxycycline, with absolute difference of 26% (95% CI = 16%-36%; P < 0.001). The proposed 2021 Centers for Disease Control and Prevention treatment guidelines designate doxycycline as the preferred agent for treatment at any site.
Relevance to patient care and clinical practice: A growing body of evidence for treatment failure following azithromycin, especially in rectal chlamydia supports updating current practice.
Conclusions: Doxycycline continues to achieve high efficacy in genital and rectal chlamydia. Clinicians should consider efficacy with convenience of dosing regimen, medication compliance, and sexual behavior risks when treating chlamydia infections.
Keywords: Chlamydia trachomatis; azithromycin; doxycycline; extragenital chlamydia; genital chlamydia; rectal chlamydia; treatment guidelines.