What is the first-line treatment for Chlamydia?

First-Line Treatment for Chlamydia

Treat uncomplicated chlamydial infection with azithromycin 1g orally as a single dose OR doxycycline 100mg orally twice daily for 7 days—both achieve 97-98% cure rates and are co-equal first-line options. 1, 2, 3

Treatment Selection Algorithm

Choose azithromycin when:

• Compliance with multi-day regimens is questionable 1, 2
• Patient has erratic health-care-seeking behavior 1
• Directly observed therapy is needed 1, 2
• Patient is pregnant (azithromycin is preferred in pregnancy) 1, 2

Choose doxycycline when:

• Cost is a primary concern (doxycycline is less expensive) 2, 3
• Patient has reliable follow-through with medication regimens 3
• Patient is not pregnant (doxycycline is absolutely contraindicated in pregnancy) 1, 2

Critical Implementation Steps

Maximize treatment success by:

• Dispensing medication on-site and directly observing the first dose (especially for azithromycin single-dose therapy) 1, 2
• Instructing patients to abstain from all sexual intercourse for 7 full days after initiating treatment, even with single-dose azithromycin, because tissue concentrations build over time 1, 2
• Ensuring abstinence continues until all sex partners have been treated 2, 3

Partner Management Requirements

All sex partners from the preceding 60 days must be:

• Evaluated and tested for chlamydia 1, 2
• Empirically treated with the same regimen regardless of symptoms or test results 1, 2
• If last sexual contact was >60 days before diagnosis, treat the most recent partner anyway 1, 2

Concurrent STI Considerations

At the initial visit when chlamydia is diagnosed:

• Test for gonorrhea, syphilis, and HIV 1
• If gonorrhea is confirmed or highly suspected (prevalence >5% in population), treat presumptively for both infections concurrently with ceftriaxone 250mg IM single dose PLUS azithromycin 1g orally single dose, as coinfection rates are 20-40% 2

Follow-Up Strategy

Test-of-cure is NOT recommended for:

• Non-pregnant patients treated with recommended regimens who are asymptomatic 1, 2
• Testing before 3 weeks post-treatment yields false-positives from dead organism DNA 1

Mandatory retesting at 3 months post-treatment for:

• All women, regardless of whether partners were reportedly treated, due to reinfection rates up to 39% in adolescent populations 1, 2
• Consider retesting men at 3 months as well, though evidence is more limited 1

Special Population: Pregnancy

Azithromycin 1g orally as a single dose is the preferred treatment during pregnancy 1, 2, 3

Alternative option:

• Amoxicillin 500mg orally three times daily for 7 days 2, 3

Absolutely contraindicated in pregnancy:

• Doxycycline 1, 2
• All fluoroquinolones (ofloxacin, levofloxacin) 2, 3

Pregnant women require:

• Mandatory test-of-cure 3-4 weeks after treatment due to potential maternal and neonatal complications 1

Alternative Regimens (When First-Line Cannot Be Used)

The CDC lists these alternatives, but they are inferior to first-line options:

• Erythromycin base 500mg orally four times daily for 7 days 2, 3
• Erythromycin ethylsuccinate 800mg orally four times daily for 7 days 2, 3
• Ofloxacin 300mg orally twice daily for 7 days 2, 3
• Levofloxacin 500mg orally once daily for 7 days 2, 3

Important caveats about alternatives:

• Erythromycin has lower efficacy and gastrointestinal side effects that lead to poor compliance 1, 3
• Fluoroquinolones offer no compliance benefit (require 7 days), are more expensive than doxycycline, and lack clinical trial validation for chlamydia 1
• Levofloxacin shows only 88-94% efficacy compared to 97-98% for first-line agents 1

Common Pitfalls to Avoid

Do NOT:

• Wait for test results if compliance with return visits is uncertain in high-prevalence populations—treat presumptively 1
• Use erythromycin as first-line therapy due to poor compliance and lower efficacy 1, 3
• Perform test-of-cure in asymptomatic non-pregnant patients treated with recommended regimens—this wastes resources and may yield false-positives 1
• Assume partners were treated without direct verification 1