What is the recommended treatment for Chlamydia (Chlamydia trachomatis)?

Chlamydia Treatment

For uncomplicated genital chlamydia in non-pregnant adults, treat with either azithromycin 1 g orally as a single dose or doxycycline 100 mg orally twice daily for 7 days—both have equivalent efficacy of approximately 97-98%. 1, 2, 3

First-Line Treatment Selection

Choose azithromycin 1 g single dose when:

• Compliance with a 7-day regimen is questionable 1, 2
• Follow-up is unpredictable or the patient has erratic health-care-seeking behavior 1, 2
• Directly observed therapy is needed, particularly in young adults 1, 3
• You can dispense medication on-site and observe the first dose 1, 2

Choose doxycycline 100 mg twice daily for 7 days when:

• Cost is a primary concern, as doxycycline is significantly less expensive 2, 3
• The patient can reliably complete a 7-day course 2
• The patient has extensive clinical experience with the medication 3

Both regimens have been validated in multiple randomized controlled trials showing equivalent efficacy, with azithromycin achieving 96% cure rates and doxycycline 98% in head-to-head comparisons. 4, 5 The FDA approves both medications for uncomplicated urethral, endocervical, or rectal chlamydial infections. 6, 7

Alternative Regimens (When First-Line Options Cannot Be Used)

Use these only when azithromycin and doxycycline are contraindicated or not tolerated: 1, 2

• Levofloxacin 500 mg orally once daily for 7 days 1, 2
• Ofloxacin 300 mg orally twice daily for 7 days 1, 2
• Erythromycin base 500 mg orally four times daily for 7 days 1, 2
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 2

Critical caveat: Erythromycin is less efficacious than first-line options and causes frequent gastrointestinal side effects leading to poor compliance—avoid unless absolutely necessary. 2, 3

Treatment During Pregnancy

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

Alternative options for pregnant patients:

• Amoxicillin 500 mg orally three times daily for 7 days 1, 2, 3
• Erythromycin base 500 mg orally four times daily for 7 days 1, 2

Absolute contraindications in pregnancy: Doxycycline, ofloxacin, and levofloxacin are contraindicated due to potential fetal harm. 1, 2

Mandatory follow-up: Pregnant women must undergo test-of-cure 3-4 weeks after treatment completion due to potential maternal and neonatal complications. 2

Pediatric Dosing

For children ≥8 years weighing >45 kg:

• Azithromycin 1 g orally as a single dose, OR 1, 2
• Doxycycline 100 mg orally twice daily for 7 days 1, 2

For children <45 kg:

• Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into four doses daily for 14 days 1, 2

For infants with chlamydial pneumonia (ages 1-3 months):

• Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into four doses daily for 14 days (approximately 80% effective; may require a second course) 1

Critical Management Steps

Medication dispensing:

• Dispense medications on-site whenever possible 1, 2
• Directly observe the first dose to maximize compliance 1, 2

Sexual abstinence requirements:

• Patients must abstain from all sexual intercourse for 7 days after initiating treatment 1, 2
• Continue abstinence until all sex partners have completed treatment 1, 2

Partner management (non-negotiable):

• All sex partners from the preceding 60 days must be evaluated, tested, and empirically treated 1, 2
• If last sexual contact was >60 days before diagnosis, still treat the most recent partner 1
• Failing to treat sex partners leads to reinfection in up to 20% of cases 1

Concurrent STI testing:

• Test all patients for gonorrhea, syphilis, and HIV at the initial visit 1
• If gonorrhea is confirmed or prevalence is high, always treat chlamydia concurrently due to substantial coinfection rates 1

Follow-Up and Retesting

Test-of-cure is NOT recommended for non-pregnant patients treated with recommended regimens because treatment failure rates are extremely low (0-3% in males, 0-8% in females). 2, 3

Exceptions requiring test-of-cure at 3-4 weeks post-treatment:

• Questionable therapeutic compliance 1, 3
• Persistent symptoms 1, 3
• Suspected reinfection 1, 3
• All pregnant patients (mandatory) 2

Critical pitfall: Testing before 3 weeks post-treatment is unreliable because nucleic acid amplification tests can yield false-positive results from dead organisms. 1

Mandatory reinfection screening:

• All women with chlamydia must be retested approximately 3 months after treatment, regardless of whether partners were reportedly treated. 1, 2
• Reinfection rates can reach 39% in some adolescent populations 2
• Repeat infections carry elevated risk for pelvic inflammatory disease and other complications compared to initial infection 1
• Men may also benefit from retesting at 3 months, though evidence is more limited 1

Common Clinical Pitfalls to Avoid

• Do not wait for test results if compliance with return visit is uncertain in high-prevalence populations—treat presumptively. 1
• Do not use non-culture tests (EIA, DFA) in children due to false-positive results from cross-reaction with other organisms. 1
• Do not rely on azithromycin to treat syphilis; antimicrobial agents used in high doses for short periods may mask or delay symptoms of incubating syphilis. 7
• Administer adequate fluids with doxycycline to reduce risk of esophageal irritation and ulceration. 6