What is the recommended treatment for a patient diagnosed with Chlamydia?

Chlamydia Treatment

For uncomplicated chlamydial infection, treat with doxycycline 100 mg orally twice daily for 7 days (98% cure rate) or azithromycin 1 g orally as a single dose (97% cure rate), with doxycycline now preferred due to superior compliance data and lower cost. 1, 2

First-Line Treatment Selection

Choose doxycycline 100 mg orally twice daily for 7 days as the default regimen for most non-pregnant adults with uncomplicated genital chlamydia. 1, 2 This achieves approximately 98% microbial cure and has extensive clinical experience over decades. 1

Switch to azithromycin 1 g orally as a single dose when:

• Compliance with a 7-day regimen is questionable or unpredictable 1, 2
• The patient has erratic health-care-seeking behavior 2
• You can directly observe therapy on-site 1, 2

The single-dose azithromycin regimen achieves 97% cure rates and eliminates compliance concerns entirely. 1, 2

Treatment Implementation

Dispense medication on-site whenever possible and directly observe the first dose to maximize compliance, particularly with azithromycin. 1, 2

Instruct patients to abstain from all sexual intercourse for 7 days after initiating treatment (for single-dose therapy) or until completion of the full 7-day regimen (for doxycycline). 1, 2 Patients must continue abstinence until all sex partners have been treated. 2

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

Use these alternatives only when azithromycin and doxycycline are contraindicated or not tolerated:

• Levofloxacin 500 mg orally once daily for 7 days (88-94% efficacy, but lacks clinical trial validation for chlamydia) 2
• Ofloxacin 300 mg orally twice daily for 7 days (similar efficacy to first-line agents but more expensive with no compliance advantage) 1, 2
• Erythromycin base 500 mg orally four times daily for 7 days (lower efficacy, poor compliance due to gastrointestinal side effects) 1, 2
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 2

Avoid erythromycin as first-line treatment because gastrointestinal side effects frequently lead to poor compliance and treatment failure. 1, 2

Treatment During Pregnancy

Azithromycin 1 g orally as a single dose is the preferred treatment during pregnancy. 2, 3 This provides optimal compliance and safety.

Alternative option: Amoxicillin 500 mg orally three times daily for 7 days. 1, 2

Second-line alternatives if azithromycin cannot be tolerated:

• Erythromycin base 500 mg orally four times daily for 7 days 1, 2
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 2

Absolute contraindications in pregnancy:

• Doxycycline 2, 3
• All fluoroquinolones (ofloxacin, levofloxacin) 2
• Erythromycin estolate (causes drug-related hepatotoxicity) 2

Pregnant women require test-of-cure 3-4 weeks after treatment completion due to lower efficacy of alternative regimens and higher rates of gastrointestinal side effects. 2

Pediatric Dosing

For children ≥8 years weighing >45 kg (100 lbs):

• Azithromycin 1 g orally as a single dose, OR 2
• Doxycycline 100 mg orally twice daily for 7 days 2, 4

For children <45 kg:

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

For neonates with chlamydial conjunctivitis or 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 second course) 2
• Alternative: Azithromycin suspension 20 mg/kg/day orally once daily for 3 days 2

Never use non-culture tests (EIA, DFA) in children due to false-positive results from cross-reaction with other organisms. 2

Partner Management

Treat all sex partners from the previous 60 days empirically without waiting for test results. 1, 2 Sex partners have substantially increased risk of chlamydial infection, and delaying treatment increases complications and ongoing transmission. 2

If the last sexual contact was >60 days before diagnosis, treat the most recent partner. 1, 2

Use the same treatment regimen for partners as for the index patient. 2 Failing to treat sex partners leads to reinfection in up to 20% of cases. 2

Coinfection with Gonorrhea

If gonorrhea is confirmed or prevalence is high (>5%) in your patient population, treat for both infections concurrently:

• Ceftriaxone 250 mg IM single dose PLUS azithromycin 1 g orally single dose 2, 5

Coinfection rates are 20-40% in populations with high gonorrhea prevalence. 2 Never treat chlamydia alone when gonorrhea is present, as this leads to treatment failure. 2

Follow-Up and Test-of-Cure

Test-of-cure is NOT recommended for non-pregnant patients treated with recommended regimens (azithromycin or doxycycline) unless:

• Therapeutic compliance is questionable 1, 2
• Symptoms persist after treatment 1, 2
• Reinfection is suspected 1, 2

Do not test before 3 weeks post-treatment because nucleic acid amplification tests yield false-positive results from dead organisms that persist after successful treatment. 2

Retest all women approximately 3 months after treatment to screen for reinfection, regardless of whether partners were reportedly treated. 1, 2 Reinfection rates reach up to 39% in some adolescent populations, and repeat infections carry elevated risk for pelvic inflammatory disease and complications. 2

Consider retesting men at 3 months, though evidence is more limited. 2

Additional STI Testing

Test all patients diagnosed with chlamydia for gonorrhea, syphilis, and HIV at the initial visit. 2

Persistent or Recurrent Symptoms

If symptoms persist after completing treatment:

• Document objective signs of urethral inflammation or laboratory evidence of infection before retreating 2
• Consider testing for Mycoplasma genitalium using NAAT on first-void urine or urethral swab 2
• For confirmed M. genitalium infection, treat with moxifloxacin 400 mg orally once daily for 7 days (highly effective for macrolide-resistant strains) 2

Do NOT retreat based on symptoms alone without objective findings. 2

Special Clinical Scenarios

Combined chlamydia and bacterial vaginosis:

• Doxycycline 100 mg orally twice daily for 7 days PLUS metronidazole 500 mg orally twice daily for 7 days 3
• Warn patients to avoid alcohol during metronidazole treatment and for 24 hours afterward (disulfiram-like reaction) 3

Patients with HIV:

• Use the same treatment regimens as HIV-negative patients 1, 3

Presumptive treatment without testing is warranted for:

• Patients with nongonococcal urethritis (NGU) 6
• Patients with pelvic inflammatory disease (PID) 6
• Patients with epididymitis 6
• Patients with mucopurulent cervicitis (MPC) in most settings 6
• Sex partners of infected patients 6, 2

Critical Pitfalls to Avoid

• Do not wait for test results before treating symptomatic patients or their partners when compliance with return visits is uncertain in high-prevalence populations 2
• Do not assume partners were treated—directly verify or use expedited partner therapy strategies 2
• Do not perform test-of-cure in asymptomatic patients treated with recommended regimens, as this wastes resources and may yield false-positive results 2
• Do not use fluoroquinolones as first-line therapy—they are more expensive than doxycycline, require 7 days of treatment (no compliance benefit), and lack clinical trial validation for levofloxacin 2
• Do not use doxycycline, fluoroquinolones, or erythromycin estolate during pregnancy 2, 3