What is the recommended treatment for a patient diagnosed with 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 97-98% cure rates and are equally effective. 1, 2, 3

First-Line Treatment Selection

Choose azithromycin when:

• Compliance with a 7-day regimen is questionable 1, 2, 3
• Follow-up is unpredictable 1, 2
• Directly observed therapy is needed 1, 3
• Treating young adults or populations with erratic health-care-seeking behavior 1, 3

Choose doxycycline when:

• Cost is a primary concern (significantly less expensive than azithromycin) 3
• The patient can reliably complete a 7-day course 3
• You have extensive clinical experience with the medication 2

Meta-analyses of 12 randomized clinical trials confirm azithromycin and doxycycline have equivalent efficacy for genital chlamydial infections, with similar rates of mild-to-moderate side effects. 2, 4, 5

Treatment During Pregnancy

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

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 (if azithromycin cannot be tolerated) 1, 3, 6

Absolute contraindications in pregnancy:

• Doxycycline 1, 3
• Ofloxacin 1, 3
• Levofloxacin 1, 3
• All fluoroquinolones 1, 3

Critical pitfall: Erythromycin estolate is contraindicated during pregnancy due to drug-related hepatotoxicity. 1 Use erythromycin base or ethylsuccinate instead. 6

Mandatory follow-up for pregnant patients: Test-of-cure is required 3-4 weeks after treatment completion due to potential maternal and neonatal complications. 3

Pediatric Dosing

For children ≥8 years weighing >45 kg:

• Azithromycin 1 g orally as a single dose, OR 1, 3
• Doxycycline 100 mg orally twice daily for 7 days 1, 3

For children <45 kg:

• Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into four doses daily for 14 days 1, 3

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 a second course) 1, 6
• Alternative: Azithromycin suspension 20 mg/kg/day orally once daily for 3 days 1

Critical pitfall: Do not use non-culture tests (EIA, DFA) in children due to false-positive results from cross-reaction with other organisms. 1

Alternative Treatment Regimens

Use these alternatives ONLY when first-line options cannot be used: 2, 3

• Erythromycin base 500 mg orally four times daily for 7 days 1, 2, 6
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 2
• Ofloxacin 300 mg orally twice daily for 7 days 1, 2
• Levofloxacin 500 mg orally once daily for 7 days 1, 2

Important limitations of alternatives:

• Erythromycin is less efficacious than azithromycin or doxycycline, with frequent gastrointestinal side effects causing poor compliance 1, 2, 3
• Fluoroquinolones (ofloxacin, levofloxacin) offer no compliance benefit over doxycycline (both require 7 days), are more expensive, and have inferior evidence 1
• Levofloxacin has only 88-94% efficacy compared to 97-98% for first-line agents and lacks clinical trial validation for chlamydia 1

Critical Management Steps

Medication dispensing:

• Dispense medications on-site when possible 1, 2, 3
• Directly observe the first dose to maximize compliance 1, 2, 3

Sexual activity restrictions:

• Patients must abstain from all sexual intercourse for 7 days after initiating treatment 1, 3
• Continue abstinence until all sex partners have completed treatment 1, 3

Partner management:

• All sex partners from the preceding 60 days must be evaluated, tested, and empirically treated 1, 2, 3
• If last sexual contact was >60 days before diagnosis, treat the most recent partner 1, 2
• Treat partners empirically without waiting for test results—delaying treatment increases risk of complications and ongoing transmission 1
• Failing to treat sex partners leads to reinfection in up to 20% of cases 1

Coinfection Considerations

If gonorrhea is confirmed or prevalence is high (>5%) in the patient population:

• Treat for both infections concurrently with ceftriaxone 250 mg IM single dose PLUS azithromycin 1 g orally single dose 1
• Coinfection rates are 20-40% in populations with high gonorrhea prevalence 1

Additional STI testing at initial visit:

• Test for gonorrhea, syphilis, and HIV 1

Follow-Up and Retesting

Test-of-cure is NOT recommended for non-pregnant patients treated with recommended regimens because cure rates exceed 97-98%. 1, 2, 3

Exceptions requiring test-of-cure (perform 3-4 weeks after treatment completion):

• Questionable therapeutic compliance 1, 2, 3
• Persistent symptoms 1, 2, 3
• Suspected reinfection 1, 2, 3

Critical pitfall: 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, 3

Mandatory reinfection screening:

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

Management of Treatment Failure

If azithromycin fails:

• Switch to doxycycline 100 mg orally twice daily for 7 days (equivalent 97-98% efficacy) 3
• Wait at least 3 weeks after initial treatment before performing confirmation tests to avoid false positives 3
• Reverify that all sexual partners from the last 60 days were adequately treated 3
• Patient must abstain from sexual intercourse for 7 complete days after starting new treatment 3

If symptoms persist after completing treatment:

• Consider testing for Mycoplasma genitalium using NAAT on first-void urine or urethral swab (causes doxycycline-resistant urethritis) 1
• For confirmed M. genitalium infection: moxifloxacin 400 mg orally once daily for 7 days is highly effective, particularly for macrolide-resistant strains 1

Critical pitfall: Do not retreat based on symptoms alone without documenting objective signs of urethral inflammation or laboratory evidence of infection. 1