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 achieve approximately 97-98% cure rates and are equally effective. 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 (can be given on-site and witnessed) 1, 3
• Treating young adults or adolescent populations where adherence is typically poor 1, 2

Choose doxycycline 100 mg twice daily for 7 days when:

• Cost is a primary concern (doxycycline is significantly less expensive) 2, 3
• The patient can reliably complete a 7-day course 2
• There is extensive clinical experience and comfort with this regimen 3

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

Use these alternatives only if 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 azithromycin or doxycycline and causes frequent gastrointestinal side effects leading to poor compliance—avoid unless absolutely necessary. 2, 3

Important note on levofloxacin: This has not been evaluated in clinical trials for chlamydia; efficacy is extrapolated from pharmacologic similarity to ofloxacin and in vitro activity only—it should not be considered equivalent to first-line therapy. 1

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 2, 3

Absolute contraindications in pregnancy:

• Doxycycline (causes fetal harm) 1, 2
• All fluoroquinolones including ofloxacin and levofloxacin 1, 2

Mandatory follow-up for pregnant patients: Test-of-cure must be performed 3-4 weeks after treatment completion due to potential maternal and neonatal complications and because alternative regimens have lower efficacy. 2

Pediatric Dosing

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

• 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 1-3 months with chlamydial pneumonia:

• 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 to Prevent Treatment Failure

Dispense medications on-site when possible and directly observe the first dose to maximize compliance. 1, 2, 3

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
• Failure to treat partners leads to reinfection in up to 20% of cases 1

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

Concurrent STI Testing and Coinfection Management

At the initial visit, test all chlamydia-positive patients for:

• Gonorrhea (coinfection is common—if gonorrhea is confirmed, always treat chlamydia concurrently) 1
• Syphilis 1
• HIV 1

If gonorrhea prevalence is high or testing unavailable, treat presumptively for both infections—treating chlamydia alone when gonorrhea is present leads to treatment failure. 1

Follow-Up and Retesting Strategy

Test-of-cure is NOT recommended for non-pregnant patients treated with azithromycin or doxycycline 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 to avoid: Testing before 3 weeks post-treatment is unreliable because nucleic acid amplification tests can yield false-positive results from dead organisms that persist after successful treatment. 1

Reinfection screening (distinct from test-of-cure):

• 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

Additional Preventive Measures

Offer at the initial visit:

• HPV vaccination referral 1
• Smoking cessation counseling 1
• Influenza vaccine 1