What is the recommended treatment for a patient diagnosed with chlamydia, considering potential allergies and pregnancy?

Treatment for Chlamydia

For uncomplicated chlamydial infection 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, 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 2
• Directly observed therapy is needed 1, 3
• Treating young adults or populations with erratic health-care-seeking behavior 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
• There is extensive clinical experience with this regimen 3

Both regimens have equivalent efficacy based on meta-analyses of 12 randomized clinical trials, with similar rates of mild-to-moderate side effects. 3 The CDC recommends dispensing medications on-site when possible and directly observing the first dose to maximize compliance. 1, 2

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

Absolute contraindications in pregnancy:

• Doxycycline 1, 2, 4
• Ofloxacin 1, 2
• Levofloxacin 1, 2
• All fluoroquinolones 1, 2
• Erythromycin estolate (due to drug-related hepatotoxicity) 1

Critical follow-up for pregnant patients: Test-of-cure is mandatory 3-4 weeks after treatment completion due to potential maternal and neonatal complications. 2

Patients with Penicillin or Macrolide Allergies

If the patient cannot tolerate azithromycin or doxycycline, use alternative regimens:

• 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
• Erythromycin ethylsuccinate 800 mg orally four times daily for 7 days 1, 2

Important caveats: Erythromycin is less efficacious than azithromycin or doxycycline and has frequent gastrointestinal side effects that lead to poor compliance, making it a less desirable choice. 1, 2, 3 Fluoroquinolones offer no compliance benefit over doxycycline (both require 7 days), are more expensive, and have inferior evidence bases. 1

Pediatric Dosing

For children ≥8 years weighing >45 kg (100 lbs):

• Azithromycin 1 g orally as a single dose, OR 1, 2
• Doxycycline 100 mg orally twice daily for 7 days 1, 2, 4

For children <45 kg:

• Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into four doses daily for 14 days 1, 2, 5

For neonates with chlamydial conjunctivitis or pneumonia (ages 1-3 months):

• Erythromycin base or ethylsuccinate 50 mg/kg/day orally divided into four doses daily for 14 days, with approximately 80% effectiveness and possible need for a second course 1, 5
• Alternative: Azithromycin suspension 20 mg/kg/day orally once daily for 3 days 1

Critical Management Steps

Sexual activity restrictions:

• 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:

• All sex partners from the preceding 60 days must be evaluated, tested, and empirically treated 1, 2
• Treat the most recent partner even if last sexual contact was >60 days before diagnosis 1
• Failing to treat sex partners leads to reinfection in up to 20% of cases 1

Concurrent STI testing:

• Test for gonorrhea, syphilis, and HIV at the initial visit 1
• If gonorrhea is confirmed or prevalence is high, treat for both infections concurrently with ceftriaxone 250 mg IM single dose plus azithromycin 1 g orally single dose 1

Follow-Up and Retesting

Test-of-cure is NOT recommended for non-pregnant patients treated with recommended regimens, as treatment failure rates are extremely low: 0-3% in males, 0-8% in females. 2, 3

Test-of-cure IS indicated when:

• Therapeutic compliance is questionable 1, 3
• Symptoms persist 1, 3
• Reinfection is suspected 1, 3
• Patient is pregnant (mandatory 3-4 weeks after treatment) 2

Timing of test-of-cure: Wait at least 3 weeks after initial treatment before performing confirmation tests, as nucleic acid amplification tests performed before 3 weeks can detect DNA of dead organisms and yield false-positive results. 1, 2

Reinfection screening: All women with chlamydia should be retested approximately 3 months after treatment, regardless of whether partners were reportedly treated, as reinfection rates can reach 39% in some adolescent populations. 1, 2 Men may also benefit from retesting at approximately 3 months, though evidence is more limited. 1

Treatment Failure Management

If azithromycin fails, switch to doxycycline 100 mg orally twice daily for 7 days. 2

Before retreating:

• Wait at least 3 weeks after initial treatment before performing confirmation tests 2
• Reverify that all sexual partners from the last 60 days were adequately treated 2
• Consider testing for Mycoplasma genitalium using NAAT if symptoms persist after completing treatment, 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

Common 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 retreat based on symptoms alone without documenting objective signs of urethral inflammation or laboratory evidence of infection 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 assume partners were treated—directly verify or use expedited partner therapy strategies 1
• Do NOT use non-culture tests (EIA, DFA) in children due to risk of false-positive results from cross-reaction with other organisms 1