What is the first line treatment for chlamydia?

First-Line Treatment for Chlamydia

For uncomplicated genital chlamydia in non-pregnant adults, use 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

Treatment Selection Algorithm

Choose azithromycin when:

• Compliance with multi-day regimens is questionable 1, 2
• Directly observed therapy is needed 1
• Patient has erratic health-care-seeking behavior 1
• Follow-up is unpredictable (more cost-effective in this scenario) 1

Choose doxycycline when:

• Cost is a primary concern (doxycycline is less expensive) 1, 2
• Patient can reliably complete 7-day course 2
• Rectal chlamydia is present (doxycycline has 99.6% efficacy vs. azithromycin's 82.9% for rectal infections) 3

Dosing Specifications

Azithromycin: 1 g orally as a single dose 1, 2, 4

Doxycycline: 100 mg orally twice daily for 7 days 1, 2, 5

Alternative Regimens

When first-line options cannot be used, the CDC recommends: 1, 2

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

Important caveat: Erythromycin is less efficacious than azithromycin or doxycycline, and gastrointestinal side effects frequently cause poor compliance. 1, 2

Special Populations

Pregnancy

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

• Alternative: Amoxicillin 500 mg orally three times daily for 7 days 1, 2
• Doxycycline and ofloxacin are absolutely contraindicated in pregnancy 1, 6
• Pregnant women should always undergo test-of-cure 3-4 weeks after treatment 1

Pediatric Patients

For children ≥8 years weighing >45 kg: 1

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

For children <45 kg: 1

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

For infants 1-3 months with chlamydial pneumonia: 1

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

Critical Implementation Steps

Maximize compliance by: 1, 2

• Dispensing medications on-site when possible
• Directly observing the first dose
• Administering doxycycline with food or milk if gastric irritation occurs 5

Sexual abstinence requirements: 1

• 7 days after single-dose azithromycin therapy OR
• Until completion of 7-day doxycycline regimen AND
• Until all sex partners are treated

Partner Management

All sex partners from the previous 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, 2
• Failing to treat partners leads to reinfection in up to 20% of cases 1

Follow-Up Protocols

Test-of-cure is NOT recommended for non-pregnant patients treated with recommended regimens who are asymptomatic, unless: 1, 2

• Therapeutic compliance is questionable
• Symptoms persist
• Reinfection is suspected

Reinfection screening at 3 months IS strongly recommended for all women regardless of partner treatment status, as repeat infections carry elevated risk for pelvic inflammatory disease. 1, 2

• Testing before 3 weeks post-treatment is unreliable due to false-positive results from dead organisms 1

Concurrent Testing Requirements

All patients diagnosed with chlamydia should be tested for: 1

• Gonorrhea (treat presumptively for chlamydia if gonorrhea is confirmed due to high coinfection rates)
• Syphilis
• HIV

Common Pitfalls to Avoid

• Do not use non-culture tests (EIA, DFA) in children due to false-positive results from cross-reaction with other organisms 1
• Do not rely on azithromycin alone for rectal chlamydia—doxycycline is significantly more effective (99.6% vs. 82.9%) 3
• Do not perform test-of-cure before 3 weeks—nucleic acid amplification tests yield false-positives from dead organisms 1
• Do not use erythromycin as first-line—poor compliance from gastrointestinal side effects makes it inferior 1, 2