What are the guidelines for treating chlamydia (Chlamydia trachomatis)?

Chlamydia Treatment Guidelines

First-Line Treatment Recommendations

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 achieving 97-98% cure rates. 1, 2

Choosing Between First-Line Options

• Azithromycin is preferred when compliance is uncertain (adolescents, populations with erratic healthcare-seeking behavior, or when follow-up is unpredictable) because it can be directly observed and eliminates adherence concerns 1, 2, 3
• Doxycycline is preferred when cost is a primary concern and the patient is reliable, as it has extensive clinical experience and lower cost 1, 2
• Both medications have similar mild-to-moderate gastrointestinal side effects (17-20% of patients) 2, 4

Practical Implementation

• Dispense medications on-site whenever possible and directly observe the first dose to maximize compliance 1, 2
• Patients must abstain from all sexual intercourse for 7 days after initiating treatment and until all sex partners have been treated 1, 3

Alternative Treatment Regimens

When first-line options cannot be used, alternative regimens include 1, 2, 3:

• Levofloxacin 500 mg orally once daily for 7 days
• Ofloxacin 300 mg orally twice daily for 7 days (contraindicated in pregnancy and patients ≤17 years)
• Erythromycin base 500 mg orally four times daily for 7 days (less desirable due to poor compliance from gastrointestinal side effects)
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days

Common pitfall: Erythromycin has significantly worse compliance due to gastrointestinal side effects and should only be used when other options are contraindicated 1, 3

Treatment During Pregnancy

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

Alternative Options for Pregnancy

• Amoxicillin 500 mg orally three times daily for 7 days if azithromycin cannot be used 1, 2
• Erythromycin base 500 mg orally four times daily for 7 days (if tolerated) 5, 2
• Erythromycin base 250 mg orally four times daily for 14 days (reduced dose for intolerance) 5

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

Critical difference: Pregnant women MUST receive test-of-cure 3-4 weeks after treatment completion due to lower efficacy of alternative regimens 1

Pediatric Treatment

Children ≥8 years weighing >45 kg:

• Azithromycin 1 g orally as a single dose OR
• Doxycycline 100 mg orally twice daily for 7 days 5, 1

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 5, 1
• Treatment effectiveness is approximately 80%; a second course may be required 5, 1

Critical diagnostic consideration: Never use non-culture tests (EIA, DFA) in children due to false-positive results from cross-reaction with other organisms; culture confirmation is mandatory, especially when sexual abuse is suspected 5, 1

Partner Management and Sexual Activity

All sex partners from the previous 60 days must be evaluated, tested, and empirically treated regardless of symptoms. 1, 2, 3

• If last sexual contact was >60 days before diagnosis, still treat the most recent partner 1, 2
• Failing to treat partners leads to reinfection in up to 20% of cases 3
• Patients must abstain from sexual intercourse until 7 days after treatment initiation AND until all partners are treated 1, 3

Coinfection with Gonorrhea

When gonorrhea is confirmed, always treat for chlamydia concurrently due to coinfection rates of 20-40%. 3

• Routine dual therapy without testing for chlamydia is cost-effective in populations with high coinfection rates 3
• All patients diagnosed with chlamydia should be tested for gonorrhea, syphilis, and HIV at the initial visit 1

Follow-Up and Test-of-Cure

Test-of-cure is NOT recommended for non-pregnant patients treated with azithromycin or doxycycline due to 97-98% cure rates. 1, 2

When Test-of-Cure IS Indicated:

• Pregnancy (mandatory) 1
• Questionable therapeutic compliance 1, 2
• Persistent symptoms 1, 2
• Suspected reinfection 1, 2

Critical timing: Testing before 3 weeks post-treatment is unreliable because nucleic acid amplification tests 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 to screen for reinfection, regardless of whether partners were reportedly treated. 1, 2, 3

• Repeat infections carry elevated risk for pelvic inflammatory disease and complications compared to initial infection 1, 3
• Men may also benefit from retesting at 3 months, though evidence is more limited 1
• High reinfection rates (up to 39% in some adolescent populations) make this screening critical 5

Key Clinical Considerations

Sequelae Prevention

• Approximately 20% of women with untreated chlamydial lower genital tract infection develop pelvic inflammatory disease 6
• Approximately 4% develop chronic pelvic pain, 3% infertility, and 2% adverse pregnancy outcomes 6
• Chlamydial PID is the most important preventable cause of infertility and adverse pregnancy outcome 6

Treatment Failure Rates

• Treatment failure with recommended regimens is uncommon: 0-3% for males and 0-8% for females 2
• Most "failures" at follow-up represent reinfection rather than true treatment failure 7

Common pitfall: Do not confuse reinfection (detected at 3 months) with treatment failure (detected at 3-4 weeks) — they require different management approaches 1