Treatment of Chlamydia
Doxycycline 100 mg orally twice daily for 7 days is the preferred first-line treatment for chlamydial infections due to its higher efficacy (95.5% for urogenital and 96.9% for rectal infections). 1
First-line Treatment Options
For Non-Pregnant Adults:
- First choice: Doxycycline 100 mg orally twice daily for 7 days 1, 2
- Higher efficacy for both urogenital (95.5%) and rectal infections (96.9%)
- Cost-effective option
- Should be taken with food or milk if gastric irritation occurs 2
For Pregnant Women:
- First choice: Azithromycin 1 g orally in a single dose 1
- Doxycycline is contraindicated in pregnancy 1
Alternative Treatment Options
Azithromycin 1 g orally in a single dose 1
- Advantages: Single-dose improves adherence, allows for directly observed therapy
- Disadvantages: Lower efficacy (92% for urogenital, only 76.4% for rectal infections)
- Consider when compliance with 7-day regimen is a concern
Other alternatives (when first-line options cannot be used) 1:
- 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 daily for 7 days
Special Populations
Children:
- Under 8 years: Erythromycin base 50 mg/kg/day divided into four doses daily for 10-14 days 1, 3
- 8 years or older but <45 kg: Age-appropriate doxycycline dosing 1
- ≥45 kg: Adult dosing regimens 1
Partner Management
- Sex partners should be evaluated and treated if they had sexual contact with the infected individual during the 60 days preceding symptom onset or diagnosis 1
- The most recent sex partner should be evaluated and treated even if the last sexual contact was >60 days before symptom onset 1
- Expedited partner therapy may be considered for heterosexual partners unlikely to seek evaluation 1
Follow-up Recommendations
- Patients should complete the entire course of medication even if symptoms resolve quickly 1
- Abstain from sexual activity for 7 days after treatment initiation and until all partners are treated 1
- Routine test of cure is not recommended if symptoms resolve 1
- Retesting is recommended 3-6 months after treatment due to high risk of reinfection 1
Clinical Considerations
Evidence Strength
The recommendation for doxycycline as first-line therapy is based on comparative efficacy data showing superior outcomes, particularly for rectal infections where doxycycline has a 20% higher cure rate compared to azithromycin (96.9% vs 76.4%) 1, 4.
Common Pitfalls
- Inadequate partner treatment: Failure to treat partners is a major cause of reinfection
- Poor adherence: The 7-day doxycycline regimen requires better adherence than single-dose azithromycin
- Inappropriate treatment for rectal infections: Using azithromycin for rectal chlamydia may result in treatment failure due to its lower efficacy for this site 1, 4
- Contraindication oversight: Doxycycline should not be used in pregnant women 1, 2
Complications of Untreated Infection
- Women: Pelvic inflammatory disease (PID), tubal scarring, infertility, ectopic pregnancy (8-30% of women with untreated chlamydia develop upper reproductive tract infection) 1
- Men: Epididymitis, urethritis, reactive arthritis
- Both: Increased risk of HIV transmission