Treatment for Chlamydia
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 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, 2
- 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
- You have extensive clinical experience 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, 4
- Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 2
Important caveat: Erythromycin is less efficacious than first-line options and causes frequent gastrointestinal side effects leading to poor compliance, making it a less desirable choice. 1, 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, 4
Absolute contraindications in pregnancy: Doxycycline, ofloxacin, and levofloxacin are absolutely contraindicated due to potential fetal harm. 1, 2
Mandatory follow-up: Pregnant women must undergo test-of-cure 3-4 weeks after treatment completion, preferably by culture, due to use of alternative regimens with lower efficacy. 1
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, 5
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, 4
Critical Management Steps
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 (mandatory to prevent reinfection):
- 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 high 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). 1, 2, 3
Test-of-cure IS indicated only when:
- Therapeutic compliance is questionable 1, 3
- Symptoms persist after treatment 1, 3
- Reinfection is suspected 1, 3
- Patient is pregnant (mandatory 3-4 weeks post-treatment) 1
Timing caveat: Testing before 3 weeks post-treatment is unreliable because nucleic acid amplification tests can yield false-positive results from dead organisms. 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 1
- 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 Pitfalls to Avoid
Medication administration:
- Dispense medications on-site when possible and directly observe the first dose to maximize compliance 1, 2
- Administer doxycycline with adequate fluids to reduce risk of esophageal irritation and ulceration 5
- If gastric irritation occurs with doxycycline, give with food or milk (absorption is not markedly affected) 5
Diagnostic testing in children:
- Do not use non-culture tests (EIA, DFA) in children due to false-positive results from cross-reaction with other organisms 1
Treatment delays:
- Do not wait for test results if compliance with return visit is uncertain in high-prevalence populations—treat presumptively 1