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

Chlamydia Treatment

For uncomplicated chlamydial infection, treat with either azithromycin 1 g orally as a single dose or doxycycline 100 mg orally twice daily for 7 days, both achieving 97-98% cure rates. 1, 2, 3

First-Line Treatment Selection

Choose between two equally effective options based on patient-specific factors:

Azithromycin 1 g single dose

• Preferred when compliance is uncertain or follow-up is unpredictable 1, 2, 3
• Allows directly observed therapy, eliminating compliance concerns 1, 2
• Particularly useful in young adults and populations with erratic health-care-seeking behavior 1, 3
• More cost-effective when follow-up is unpredictable 1
• Microbial cure rate: 97% 2, 3

Doxycycline 100 mg twice daily for 7 days

• Preferred when cost is the primary concern, as it is significantly less expensive than azithromycin 2, 3
• Requires patient ability to reliably complete 7-day course 3
• Extensive clinical experience over longer period 1
• Microbial cure rate: 98% 2, 3
• FDA-approved dosing: 100 mg every 12 hours for 7 days 4

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

Alternative Regimens (Second-Line Only)

Use only when first-line options cannot be used due to allergy or intolerance:

• Levofloxacin 500 mg orally once daily for 7 days (88-94% efficacy, lacks clinical trial validation) 1, 3
• Ofloxacin 300 mg orally twice daily for 7 days (similar efficacy to first-line but more expensive, no compliance advantage) 5, 1, 3
• Erythromycin base 500 mg orally four times daily for 7 days (less efficacious, frequent GI side effects reduce compliance) 1, 2, 3
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 2

Common pitfall: Fluoroquinolones offer no compliance benefit over doxycycline (both require 7 days), cost more, and have inferior evidence 1

Treatment During Pregnancy

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

Alternative options for pregnant women:

• Amoxicillin 500 mg orally three times daily for 7 days 5, 1, 3
• Erythromycin base 500 mg orally four times daily for 7 days 5, 1, 3
• Erythromycin base 250 mg orally four times daily for 14 days 5
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 5
• Erythromycin ethylsuccinate 400 mg orally four times daily for 14 days 5

Absolute contraindications in pregnancy: Doxycycline, ofloxacin, levofloxacin, and all fluoroquinolones 5, 1, 3

Critical difference: Pregnant women MUST undergo test-of-cure 3-4 weeks after treatment completion due to alternative regimens having lower efficacy and higher GI side effects 1, 3

Warning: Erythromycin estolate is contraindicated during pregnancy due to drug-related hepatotoxicity 5

Pediatric Dosing

Children ≥8 years weighing >45 kg:

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

Children <45 kg:

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

Infants with chlamydial pneumonia (1-3 months):

• Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into four doses daily for 14 days 1
• Effectiveness approximately 80%; second course may be needed 1

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

Mandatory Patient Instructions

Sexual abstinence requirements:

• Abstain from ALL sexual intercourse for 7 days after initiating treatment 1, 2, 3
• Continue abstinence until ALL sex partners complete treatment 1, 2, 3
• This applies regardless of which regimen is used 1

Partner management:

• All sex partners from the preceding 60 days must be evaluated, tested, and empirically treated 1, 2, 3
• Treat the most recent partner even if last sexual contact was >60 days before diagnosis 1, 2
• Failing to treat sex partners leads to reinfection in up to 20% of cases 1

Follow-Up and Retesting

Test-of-cure (NOT routinely recommended):

• Do NOT perform test-of-cure for non-pregnant patients treated with recommended regimens (failure rates: 0-3% males, 0-8% females) 1, 3
• Only perform if therapeutic compliance is questionable, symptoms persist, or reinfection is suspected 1, 2
• Wait at least 3 weeks after treatment completion before testing, as earlier testing yields false-positives from dead organism DNA 1, 3

Reinfection screening (MANDATORY):

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

Coinfection Considerations

• Test all patients for gonorrhea, syphilis, and HIV at initial visit 1
• If gonorrhea is confirmed, always treat chlamydia concurrently due to high coinfection rates 1, 2
• In high-prevalence populations where gonorrhea testing is unavailable, treat presumptively for both infections 1

Treatment Failure Management

If azithromycin fails (rare: 0-3% in males, 0-8% in females):

1. Switch to doxycycline 100 mg orally twice daily for 7 days (equivalent 97-98% efficacy) 3
2. Wait at least 3 weeks before confirmation testing to avoid false-positives 3
3. Reverify that all sexual partners from last 60 days were adequately treated 3
4. Patient must abstain from sexual intercourse for 7 complete days after starting new treatment 3
5. Schedule retest 3 months after successful treatment 3

Alternative options if doxycycline cannot be used: Ofloxacin 300 mg twice daily for 7 days or levofloxacin 500 mg once daily for 7 days (both contraindicated in pregnancy) 3