What is the recommended treatment for an adult patient diagnosed with uncomplicated Chlamydia (Chlamydia trachomatis)?

Treatment of Uncomplicated Chlamydia in Adults

For uncomplicated genital chlamydia in 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 first-line options. 1, 2, 3

First-Line Treatment Selection

The choice between azithromycin and doxycycline depends on specific clinical circumstances:

• Azithromycin 1 g orally, single dose is preferred when:

  • Compliance is uncertain or follow-up is unpredictable 1, 3
  • Directly observed therapy is needed 1, 2
  • The patient has erratic health-care-seeking behavior 1
  • Single-dose convenience outweighs cost considerations 3

• Doxycycline 100 mg orally twice daily for 7 days is preferred when:

  • Cost is a primary concern (significantly less expensive than azithromycin) 1, 3
  • The patient is reliable with multi-day regimens 3
  • Extensive clinical experience is valued 2, 3

Both regimens have similar mild-to-moderate gastrointestinal side effects (17-20% of patients). 4, 5

Alternative Treatment Regimens

When first-line options cannot be used due to allergy or intolerance, alternative regimens include:

• Erythromycin base 500 mg orally four times daily for 7 days 1, 2, 3
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 3
• Ofloxacin 300 mg orally twice daily for 7 days 1, 3
• Levofloxacin 500 mg orally once daily for 7 days 1, 2, 3

Important caveats: Erythromycin has lower efficacy than first-line agents and causes frequent gastrointestinal side effects leading to poor compliance. 3 Fluoroquinolones (ofloxacin, levofloxacin) offer no compliance advantage over doxycycline, are more expensive, and levofloxacin has inferior evidence (88-94% efficacy vs. 97-98% for first-line agents). 1

Treatment During Pregnancy

Azithromycin 1 g orally as a single dose is the preferred treatment during pregnancy. 1, 2, 6

Alternative option for pregnant patients:

• Amoxicillin 500 mg orally three times daily for 7 days 1, 2, 3

Absolute contraindications in pregnancy: Doxycycline, ofloxacin, levofloxacin, and all fluoroquinolones are contraindicated due to potential fetal harm. 1, 2 Erythromycin estolate is also contraindicated due to drug-related hepatotoxicity. 1

If azithromycin cannot be tolerated, erythromycin base 500 mg orally four times daily for 7 days can be used. 1, 6

Implementation Best Practices

To maximize treatment success:

• Dispense medication on-site when possible and directly observe the first dose 1, 2, 3
• Patients must abstain from all sexual intercourse for 7 days after initiating treatment (regardless of regimen) and until all sex partners are treated 1, 2, 3
• Medications can be taken without regard to meals, though optimal absorption occurs in the fasting state 6

Coinfection Management

If gonorrhea is confirmed or prevalence is high in your population, treat for both infections concurrently with ceftriaxone 250 mg IM single dose plus azithromycin 1 g orally single dose, as coinfection rates are 20-40%. 7, 2

All chlamydia patients should be tested for:

• Gonorrhea 2
• Syphilis 2
• HIV 2

Partner Management

All sex partners from the previous 60 days must be evaluated, tested, and empirically treated with a chlamydia-effective regimen, even if asymptomatic. 1, 3 If the last sexual contact was >60 days before diagnosis, the most recent partner should still be treated. 1, 3

Failing to treat sex partners leads to reinfection in up to 20% of cases. 1

Follow-Up and Reinfection Screening

Test-of-cure is NOT recommended for non-pregnant patients treated with recommended regimens who are asymptomatic, as cure rates exceed 97%. 1, 2, 3 Testing before 3 weeks post-treatment is unreliable because nucleic acid amplification tests can yield false-positive results from dead organisms. 1

Mandatory reinfection screening at 3 months is strongly recommended for all women with chlamydia, as reinfection rates reach 39% in some populations and carry elevated risk for pelvic inflammatory disease and other complications. 1, 2, 3 Men may also benefit from retesting at 3 months, though evidence is more limited. 1

Exception: Pregnant women should always undergo test-of-cure 3-4 weeks after treatment completion, preferably by culture, due to the use of alternative regimens with lower efficacy. 1

Critical Pitfalls to Avoid

• Do NOT wait for test results if compliance with return visit is uncertain in high-prevalence populations—treat presumptively 1
• Do NOT assume partners were treated—directly verify or use expedited partner therapy strategies 1
• Do NOT perform test-of-cure in asymptomatic patients treated with recommended regimens, as this wastes resources and may yield false-positive results 1
• Do NOT retreat based on symptoms alone without documenting objective signs of urethral inflammation or laboratory evidence of infection 1

Persistent Symptoms After Treatment

If symptoms persist after completing treatment:

• Consider testing for Mycoplasma genitalium using NAAT on first-void urine or urethral swab, as this organism causes doxycycline-resistant urethritis 1
• For confirmed M. genitalium infection, moxifloxacin 400 mg orally once daily for 7 days is highly effective, particularly for macrolide-resistant strains 1