What are the first line treatment options for a patient diagnosed with chlamydia?

First-Line Treatment for Chlamydia

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

Treatment Selection Algorithm

Choose azithromycin when:

• Patient compliance with multi-day regimens is questionable 1, 2, 3
• Follow-up is unpredictable 1, 2
• Directly observed therapy is needed 1, 3
• Patient is pregnant (azithromycin is preferred in pregnancy) 1, 2

Choose doxycycline when:

• Cost is a primary concern (doxycycline is less expensive) 2, 3
• Patient can reliably complete 7-day therapy 2
• Patient is not pregnant (doxycycline is contraindicated in pregnancy) 4, 1, 2

Dosing Specifications

Azithromycin: 1 g orally as a single dose 1, 2, 3

Doxycycline: 100 mg orally twice daily for 7 days 1, 2, 3, 5

Alternative Regimens (When First-Line Options Cannot Be Used)

Use these only when patients cannot tolerate azithromycin or doxycycline:

• Erythromycin base 500 mg orally four times daily for 7 days 1, 3
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 3
• Ofloxacin 300 mg orally twice daily for 7 days 4, 1, 3
• Levofloxacin 500 mg orally once daily for 7 days 1, 3

Important caveat: Erythromycin is less efficacious than first-line options and gastrointestinal side effects frequently lead to poor compliance. 1, 3 Levofloxacin has not been evaluated in clinical trials for chlamydia and is based only on extrapolated efficacy from ofloxacin. 1

Special Population: Pregnancy

Doxycycline and all fluoroquinolones (ofloxacin, levofloxacin) are absolutely contraindicated in pregnancy. 4, 1, 2

Preferred treatment in pregnancy: Azithromycin 1 g orally as a single dose 1, 2

Alternative in pregnancy: Amoxicillin 500 mg orally three times daily for 7 days 4, 1, 3

Mandatory follow-up: Test-of-cure is required 3-4 weeks after treatment completion in pregnant women due to use of alternative regimens with lower documented efficacy. 1, 2

Special Population: Children

For children ≥8 years weighing >45 kg: Use adult dosing—azithromycin 1 g single dose or doxycycline 100 mg twice daily for 7 days 1, 2

For children <45 kg: Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into four doses daily for 14 days 1

Critical Management Requirements

Sexual abstinence: Patients must abstain from all sexual intercourse for 7 days after initiating treatment AND until all sex partners have completed treatment. 1, 2, 3 This is non-negotiable to prevent reinfection.

Partner management: All sex partners from the preceding 60 days must be evaluated, tested, and empirically treated. 1, 2, 3 Failure to treat partners leads to reinfection in up to 20% of cases. 2

Medication dispensing: Dispense medications on-site when possible and directly observe the first dose to maximize compliance. 1, 3

Follow-Up Testing

Test-of-cure is NOT recommended for non-pregnant patients treated with azithromycin or doxycycline unless therapeutic compliance is questionable, symptoms persist, or reinfection is suspected. 1, 2, 3 Testing before 3 weeks post-treatment yields false-positive results from dead organisms. 1, 2

Reinfection screening at 3 months IS mandatory for all women with chlamydia, regardless of whether partners were reportedly treated. 1, 2, 3 Reinfection rates reach up to 39% in some adolescent populations, and repeat infections carry elevated risk for pelvic inflammatory disease and complications. 1, 2

Concurrent STI Testing

At the initial visit, test all patients diagnosed with chlamydia for:

• Gonorrhea 1
• Syphilis 1
• HIV 1

If gonorrhea is confirmed or prevalence is high, treat presumptively for both infections due to substantial coinfection rates. 1, 3

Common Pitfalls to Avoid

Do not assume treatment failure when recurrence occurs—84-92% of recurrent infections are reinfections from untreated partners, not antibiotic resistance. 2 Treatment failure with recommended regimens is rare (0-3% in males, 0-8% in females). 3

Do not allow sexual activity before partner treatment is complete—both patient and all partners must complete treatment before resuming intercourse. 1, 2

Do not skip the 3-month retest in women—this is when reinfection risk is highest. 1, 2

Do not test too early after treatment—wait at least 3 weeks to avoid false-positives from dead organisms. 1, 2